Q-W1 code-review follow-ups: restore 104 trailing newlines, relocate reasampler_uid.h to core/wire, drop ext_keys namespaces shim, add slot_map_tests, golden serialize literals for 4 modules, namespaces.h/pragma-once ordering sweep. 60/60 green.

CMakeLists.txt

@@ -249,6 +249,16 @@ target_include_directories(tail_control PUBLIC src)
 target_link_libraries(tail_control PUBLIC render_settings)
 target_link_libraries(tail_control PRIVATE json)
 
+# ---------------------------------------------------------------------------
+# 2g''') Pure slot_map library — NO REAPER, NO SWELL. The L7 gap-preserving
+#        display-position carrier for one bank (extracted from bank_book, Q-W1
+#        T4-05): sample id -> slot, gap-preserving append/remove/reorder/reconcile,
+#        JSON round-trip. Mirror of bank_model; wrapped (not merged) by bank_book.
+# ---------------------------------------------------------------------------
+add_library(slot_map STATIC src/core/model/slot_map.cpp)
+target_include_directories(slot_map PUBLIC src)
+target_link_libraries(slot_map PRIVATE json)
+
 # ---------------------------------------------------------------------------
 # 2g') Pure bank_book library — NO REAPER, NO SWELL. The multi-bank phase heart
 #      (Phase B1): an ordered registry of banks (pool seeded as bank-zero + named
@@ -257,9 +267,10 @@ target_link_libraries(tail_control PRIVATE json)
 #      sample between banks, JSON round-trip + legacy-bank_index→pool migration.
 #      Mirror of bank_model / view_mode_model; wraps BankIndex (bank_model untouched).
 # ---------------------------------------------------------------------------
-add_library(bank_book STATIC src/core/model/bank_book.cpp src/core/model/slot_map.cpp)
+add_library(bank_book STATIC src/core/model/bank_book.cpp)
 target_include_directories(bank_book PUBLIC src)
 target_link_libraries(bank_book PUBLIC bank_model)
+target_link_libraries(bank_book PUBLIC slot_map)
 target_link_libraries(bank_book PRIVATE json)
 
 # ---------------------------------------------------------------------------
@@ -404,7 +415,7 @@ target_include_directories(drag_out PUBLIC src)
 #      parallel byte writer — so the cross-artifact contract cannot drift; links
 #      sample_map (which pulls bank_book/wav_trim/sampler_core transitively) and
 #      NEITHER SDK. The class-ID string derives from the FROZEN UID macros
-#      (src/shell/instrument/reasampler_uid.h, SDK-free), channel-selected via the generated
+#      (src/core/wire/reasampler_uid.h, SDK-free), channel-selected via the generated
 #      version header — hence the generated include dir. The round-trip test parses
 #      the container and decodes back through the instrument's own reader. Mirror of
 #      assignment_request.
@@ -645,6 +656,10 @@ add_executable(bank_book_tests tests/test_bank_book.cpp)
 target_link_libraries(bank_book_tests PRIVATE bank_book)
 add_test(NAME bank_book_tests COMMAND bank_book_tests)
 
+add_executable(slot_map_tests tests/test_slot_map.cpp)
+target_link_libraries(slot_map_tests PRIVATE slot_map json)
+add_test(NAME slot_map_tests COMMAND slot_map_tests)
+
 add_executable(wav_trim_tests tests/test_wav_trim.cpp)
 target_link_libraries(wav_trim_tests PRIVATE wav_trim)
 add_test(NAME wav_trim_tests COMMAND wav_trim_tests)

src/actions.h

@@ -1,5 +1,5 @@
-#include "core/namespaces.h"
 #pragma once
+#include "core/namespaces.h"
 // actions — the Design View action family (Phase D4). Registers the bindable
 // actions that drive the mode workflow and wires them end-to-end: toggle/activate
 // a mode, tag/untag/show-both the current track selection. Each action mutates the

src/bank_panel.h

@@ -1,5 +1,5 @@
-#include "core/namespaces.h"
 #pragma once
+#include "core/namespaces.h"
 // bank_panel — the docked grid window (M5, Wave A). REAPER-facing shell: it owns
 // a SWELL dialog docked via DockWindowAddEx, and paints the current project's
 // bank as a grid of LICE-drawn waveform thumbnails. The panel itself NEVER inserts

src/core/instrument/ui/envelope_overlay.cpp

@@ -55,7 +55,6 @@ int levelToY(const Rect& area, double level) {
 
 namespace {
 
-
 EnvVertex vtx(EnvNode node, const Rect& area, double totalSeconds, double t, double level) {
     EnvVertex v;
     v.node = node;

src/core/instrument/ui/param_slider.cpp

@@ -99,7 +99,6 @@ double normDeg(double deg) {
     return deg;
 }
 
-
 }  // namespace
 
 KnobGeometry computeKnob(const Rect& cell) {

src/core/wire/instrument_drop.cpp

@@ -1,12 +1,12 @@
 // instrument_drop — pure implementation. See instrument_drop.h.
 // NO REAPER / SWELL / VST3 SDK / vendor. Reuses sample_map's ComponentState serializer and
-// the SDK-free UID macros (vst/reasampler_uid.h).
+// the SDK-free UID macros (core/wire/reasampler_uid.h).
 
 #include "core/wire/instrument_drop.h"
 
 #include <cstdio>
 
-#include "shell/instrument/reasampler_uid.h"  // REASAMPLER_ACTIVE_UID_* — the FROZEN, channel-selected class UID
+#include "core/wire/reasampler_uid.h"  // REASAMPLER_ACTIVE_UID_* — the FROZEN, channel-selected class UID
 #include "core/instrument/map/sample_map.h"      // ComponentState + serializeComponentState (the SHARED writer)
 
 namespace reasampler::wire {

src/core/wire/instrument_drop.h

@@ -3,7 +3,7 @@
 //
 // PURE MODULE (CLAUDE.md §load-bearing split): NO REAPER types, NO SWELL, NO VST3 SDK,
 // NO vendor/ includes. Standard library only (+ the pure sample_map it reuses and the
-// SDK-free UID macros in vst/reasampler_uid.h). Unit-tested outside the DAW — the same
+// SDK-free UID macros in core/wire/reasampler_uid.h). Unit-tested outside the DAW — the same
 // "small pure builder + round-trip proof" pattern as assignment_request / provenance.
 //
 // -- What it is (the S17 seam, extension side) --------------------------------
@@ -43,7 +43,7 @@ namespace reasampler::wire {
 // header carries (public.sdk vstpresetfile: "ASCII-encoded FUID"). On both COM-compatible
 // (Windows GUID byte order) and plain layouts, FUID::toString reduces to the four
 // INLINE_UID uint32 words printed "%08X" in order, so this derivation is platform-stable.
-// Sourced from the FROZEN macros in vst/reasampler_uid.h (the same constants the factory
+// Sourced from the FROZEN macros in core/wire/reasampler_uid.h (the same constants the factory
 // registers), channel-selected by the one REASAMPLER_CHANNEL_IS_BETA bit — a beta extension
 // writes presets only the beta VST class accepts, preserving the S18 pairing invariant.
 std::string vstClassIdHex();

src/ext_keys.h

@@ -1,4 +1,3 @@
-#include "core/namespaces.h"
 #pragma once
 // ext_keys — the SINGLE SOURCE OF TRUTH for the "reasampler" project ext-state
 // namespace + key names, shared by the extension (writer, via persist.h) and the
@@ -27,7 +26,7 @@ namespace reasampler {
 // because the value is fixed by the channel bit at build time. This is the wire-contract
 // reconciliation between S4 (shared ext_keys) and V4 (channel-isolated namespace): without
 // it a beta instrument would read the stable namespace and see empty state.
-inline const char* kProjExtNamespace() { return extStateNamespace().c_str(); }
+inline const char* kProjExtNamespace() { return version::extStateNamespace().c_str(); }
 
 // The multi-bank key: the whole serialized BankBook (pool + named banks). This is
 // the key the VST3 instrument reads to see the live bank (read-only, S4). persist.h

src/ingest.h

@@ -1,5 +1,5 @@
-#include "core/namespaces.h"
 #pragma once
+#include "core/namespaces.h"
 // ingest — the S8 "ingest through the bank" shell (EXTENSION side).
 //
 // Compiled into the reaper_reasampler MODULE. REAPER-facing (PCM_Source metadata reads,

src/persist.h

@@ -1,5 +1,5 @@
-#include "core/namespaces.h"
 #pragma once
+#include "core/namespaces.h"
 // persist — the REAPER-facing bridge between the in-memory BankModel and project
 // ext state (CLAUDE.md §load-bearing split; CONTEXT.md §Persistence & paths).
 //

src/shell/actions/drag_out_win.h

@@ -1,5 +1,5 @@
-#include "core/namespaces.h"
 #pragma once
+#include "core/namespaces.h"
 // drag_out_win — the OS/COM initiation half of native OS drag-out (Milestone 11). The pure
 // gesture-boundary decision and path-list assembly live in drag_out.*; THIS is the platform
 // shell that hands a resolved, existing-file path list to the operating system's drag-drop

src/shell/actions/instrument_drop_win.h

@@ -1,5 +1,5 @@
-#include "core/namespaces.h"
 #pragma once
+#include "core/namespaces.h"
 // instrument_drop_win — the REAPER-facing shell half of S17 drop-and-load. The pure gesture
 // decision lives in drag_out (DragGesture::InstrumentDrop) and the pure payload construction
 // in instrument_drop; THIS is the platform shell that (a) resolves a screen point to a track

src/shell/capture/capture.h

@@ -1,5 +1,5 @@
-#include "core/namespaces.h"
 #pragma once
+#include "core/namespaces.h"
 // capture — the REAPER-facing capture shell (CLAUDE.md §load-bearing split).
 //
 // This header declares the capture *seam* the later milestones fill:

src/shell/capture/insert.h

@@ -1,5 +1,5 @@
-#include "core/namespaces.h"
 #pragma once
+#include "core/namespaces.h"
 // insert — placement of bank samples into the arrange (M6). REAPER-facing shell:
 // it reads the bank_panel's current selection, resolves each selected sample's
 // file, and drops it into the arrange at the edit cursor via InsertMedia, wrapped

src/shell/capture/item_read.h

@@ -1,5 +1,5 @@
-#include "core/namespaces.h"
 #pragma once
+#include "core/namespaces.h"
 // item_read — the ONE place a MediaItem* is read for its canonical GUID string and for
 // the durable P_LANENAME of the fixed lane it sits on. Before this seam, view.cpp and
 // bank_panel.cpp each carried a near-identical private itemGuid / itemLaneName pair

src/shell/capture/provenance_shell.h

@@ -1,5 +1,5 @@
-#include "core/namespaces.h"
 #pragma once
+#include "core/namespaces.h"
 // provenance_shell — the REAPER-facing reads Milestone 10 needs, in one place.
 //
 // The PURE provenance module (provenance.h) owns the fingerprint encoding, the

src/shell/capture/track_guid.h

@@ -1,5 +1,5 @@
-#include "core/namespaces.h"
 #pragma once
+#include "core/namespaces.h"
 // track_guid — the ONE place a MediaTrack* is formatted into the canonical GUID
 // string used as a membership-index key. Both the Design View shell (view.cpp) and
 // the actions layer (actions.cpp) key membership on this exact string, so the key

src/shell/instrument/reaper_bridge.h

@@ -1,4 +1,3 @@
-#include "core/namespaces.h"
 // reaper_bridge.h — the REAPER VST-host bridge (Phase S1 read spike). THIN shell:
 // resolves REAPER API functions by name over the host context and reads the live
 // "reasampler" project ext-state. The fiddly decode lives in bridge_marshal (pure).
@@ -17,6 +16,7 @@
 // reaper_vst3_interfaces.h + reaper_plugin_functions.h at the spike.
 
 #pragma once
+#include "core/namespaces.h"
 
 #include <optional>
 #include <string>

src/shell/instrument/reasampler_embed.h

@@ -1,4 +1,3 @@
-#include "core/namespaces.h"
 // reasampler_embed.h — the S6 embedded TCP/MCP UI shell. Implements REAPER's
 // IReaperUIEmbedInterface (vendor/reaper-sdk/sdk/reaper_plugin_fx_embed.h +
 // reaper_vst3_interfaces.h) so the instrument draws a compact keymap/level strip INLINE in
@@ -32,6 +31,7 @@
 // REAPER's messages to/from it and draws with the same LICE idiom as reasampler_editor.
 
 #pragma once
+#include "core/namespaces.h"
 
 #include <cstdint>
 #include <string>

src/shell/instrument/reasampler_vst.h

@@ -1,4 +1,3 @@
-#include "core/namespaces.h"
 // reasampler_vst.h — shared identity constants for the ReaSampler VST3 instrument
 // (Phase S). One place for the plugin's class UID, name, vendor, and version so the
 // processor, factory, and editor agree.
@@ -19,10 +18,11 @@
 // binary UID identity — the string identity lives in the pure module).
 
 #pragma once
+#include "core/namespaces.h"
 
 #include "pluginterfaces/base/funknown.h"
 
-#include "shell/instrument/reasampler_uid.h"  // the FROZEN UID macros + channel selection (SDK-free values)
+#include "core/wire/reasampler_uid.h"  // the FROZEN UID macros + channel selection (SDK-free values)
 
 namespace reasampler::vst {
 

src/shell/panel/draw_kit.h

@@ -1,5 +1,5 @@
-#include "core/namespaces.h"
 #pragma once
+#include "core/namespaces.h"
 // draw_kit — the LICE-facing SHELL half of the shared drawing kit (Phase L, L1). This is
 // the ONE source of drawing for the whole system: every surface (bank_panel now; the VST
 // editor + embed strip at L3) fills, buttons, rows, sliders, waveforms, and — above all —

src/shell/persist/usage_scan.h

@@ -1,5 +1,5 @@
-#include "core/namespaces.h"
 #pragma once
+#include "core/namespaces.h"
 // usage_scan — the EXTENSION-side shell of the pS-usage seam (see sample_usage.h for
 // the pure core, the fail-safe folds, and the full design note). At prune-scan time it
 // answers ONE question: which project-relative bank paths are held by a LIVE ReaSampler

src/shell/view/view.h

@@ -1,5 +1,5 @@
-#include "core/namespaces.h"
 #pragma once
+#include "core/namespaces.h"
 // view — the REAPER-facing shell of the Design View feature (Phase D2). It is the
 // mirror of the capture shell: the ViewModeModel (pure, D1) holds the mode/
 // membership/snapshot state and emits the toggle plan; this shell reads the live

src/vst/reasampler_editor.h

@@ -1,4 +1,3 @@
-#include "core/namespaces.h"
 // reasampler_editor.h — the VST3 IPlugView LICE editor for the ReaSampler 9000
 // capture-first UI (Phase S10). THIN shell: hosts a LICE-drawn child window inside the
 // host's IPlugView seat and routes host paint/mouse into the pure geometry modules
@@ -23,6 +22,7 @@
 // to create/destroy the child window and onSize to resize it.
 
 #pragma once
+#include "core/namespaces.h"
 
 #include <optional>
 #include <string>

src/vst/reasampler_processor.h

@@ -1,4 +1,3 @@
-#include "core/namespaces.h"
 // reasampler_processor.h — the VST3 SingleComponentEffect (Phase S4, Tier 0). Wires the
 // pure S3 sampler core into a real VSTi: it declares an event-input bus + a stereo audio
 // output bus, marshals host MIDI note-on/off into the VoiceEngine, and renders the
@@ -26,6 +25,7 @@
 // single atomic pointer swap. See the LoadedInstrument handoff below.
 
 #pragma once
+#include "core/namespaces.h"
 
 #include <atomic>
 #include <cstdint>

tests/test_bank_book.cpp

@@ -42,6 +42,29 @@ static Sample sampleWith(const std::string& seed) { return sampleWith(seed, "has
 
 // ---------------------------------------------------------------------------
 
+// Golden byte-literal (Q-W1 follow-up): pins the EXACT serialized bytes for a
+// small fixture (a freshly-seeded book: pool only, one sample), not just
+// self-consistent re-serialization — a format drift that both writer and
+// reader agree on would slip past the round-trip tests but not this. The
+// format is frozen as-shipped; the literal below is the captured current
+// output.
+static void testSerializeGoldenLiteral() {
+    BankBook book;
+    CHECK(book.pool().index.add(sampleWith("g1")) == AddResult::Added);
+    CHECK(book.serialize() ==
+          "{\"version\":1,\"activeBank\":\"pool\",\"banks\":[{\"id\":\"pool\","
+          "\"displayName\":\"Pool\",\"ordinal\":0,\"index\":{\"version\":1,"
+          "\"samples\":[{\"id\":\"id-g1\",\"displayName\":\"sample g1\","
+          "\"relativePath\":\"bank/g1.wav\",\"sourceMode\":0,\"sourceRange\":{"
+          "\"startSeconds\":0,\"endSeconds\":0,\"startPpq\":0,\"endPpq\":0},"
+          "\"trackGuids\":[],\"wetDry\":1,\"channelCount\":2,\"sampleRate\":48000,"
+          "\"lengthSeconds\":0,\"lengthBeats\":0,\"captureTempo\":0,"
+          "\"captureTimeSigNum\":0,\"captureTimeSigDenom\":0,\"key\":null,"
+          "\"rootNote\":null,\"loop\":null,\"levels\":{\"peakDb\":0,\"rmsDb\":0,"
+          "\"lufs\":0},\"clipped\":false,\"tier\":0,\"contentHash\":\"hash-g1\","
+          "\"provenance\":null,\"createdTimestamp\":1753080000}]},\"slots\":[]}]}");
+}
+
 static void testPoolSeededAndDefaults() {
     BankBook book;
     // Pool present as bank-zero with fixed id + name + ordinal 0.
@@ -790,123 +813,13 @@ static void testUpdateSampleInPlace() {
 // ===========================================================================
 // L7 — SlotMap (gap-preserving display positions) + BankBook ordering/reorder/replace
 // ===========================================================================
-
-// --- SlotMap unit behaviour --------------------------------------------------
-
-static void testSlotMapDenseAppend() {
-    SlotMap m;
-    m.append("a");
-    m.append("b");
-    m.append("c");
-    CHECK(m.slotOf("a") == 0);
-    CHECK(m.slotOf("b") == 1);
-    CHECK(m.slotOf("c") == 2);
-    CHECK(m.maxSlot() == 2);
-    CHECK((m.orderedIds() == std::vector<std::string>{"a", "b", "c"}));
-    CHECK(m.idAt(1) == "b");
-    CHECK(m.slotOf("nope") == -1);
-}
-
-static void testSlotMapRemoveLeavesGap() {
-    SlotMap m;
-    m.append("a"); m.append("b"); m.append("c");  // 0,1,2
-    CHECK(m.remove("b"));                          // slot 1 now EMPTY (no re-pack)
-    CHECK(m.slotOf("a") == 0);
-    CHECK(m.slotOf("c") == 2);                     // c did NOT shift down
-    CHECK(m.idAt(1).empty());                      // gap preserved
-    CHECK((m.orderedIds() == std::vector<std::string>{"a", "c"}));
-    CHECK(!m.remove("b"));                         // already gone
-}
-
-static void testSlotMapAppendAfterGapGoesToFrontier() {
-    SlotMap m;
-    m.append("a"); m.append("b"); m.append("c");  // 0,1,2
-    m.remove("a");                                 // slot 0 empty
-    m.append("d");                                 // append goes AFTER last occupied (2) -> 3
-    CHECK(m.slotOf("d") == 3);                      // did NOT fill the slot-0 gap
-    CHECK(m.idAt(0).empty());
-}
-
-static void testSlotMapReorderIntoEmpty() {
-    SlotMap m;
-    m.append("a"); m.append("b"); m.append("c");  // 0,1,2
-    m.remove("b");                                 // slot 1 empty
-    CHECK(m.reorder("c", 1));                       // c -> empty slot 1; its slot 2 empties
-    CHECK(m.slotOf("c") == 1);
-    CHECK(m.idAt(2).empty());
-    CHECK(m.slotOf("a") == 0);                      // untouched
-}
-
-static void testSlotMapReorderOntoOccupiedInsertsAndShifts() {
-    SlotMap m;
-    m.append("a"); m.append("b"); m.append("c"); m.append("d");  // 0,1,2,3
-    CHECK(m.reorder("d", 1));   // d onto occupied slot 1 -> insert-before, shift b,c up
-    CHECK(m.slotOf("a") == 0);  // before the target: unchanged
-    CHECK(m.slotOf("d") == 1);  // took the target slot
-    CHECK(m.slotOf("b") == 2);  // shifted +1
-    CHECK(m.slotOf("c") == 3);  // shifted +1
-    CHECK((m.orderedIds() == std::vector<std::string>{"a", "d", "b", "c"}));
-}
-
-static void testSlotMapReorderPreservesInteriorGapAboveTarget() {
-    SlotMap m;
-    m.append("a"); m.append("b"); m.append("c");  // 0,1,2
-    m.remove("b");                                 // gap at 1: a@0, c@2
-    m.append("d");                                 // d@3
-    CHECK(m.reorder("d", 0));   // d onto occupied slot 0 -> a shifts to 1, c shifts to 3
-    CHECK(m.slotOf("d") == 0);
-    CHECK(m.slotOf("a") == 1);  // shifted from 0 -> 1
-    CHECK(m.slotOf("c") == 3);  // shifted from 2 -> 3 (gap at 2 preserved as a +1 of its own)
-    CHECK(m.idAt(2).empty());   // interior gap above the target survives
-}
-
-static void testSlotMapReorderUnmappedIsNoOp() {
-    SlotMap m;
-    m.append("a");
-    CHECK(!m.reorder("ghost", 0));  // not mapped -> false, no mutation
-    CHECK(m.slotOf("a") == 0);
-}
-
-static void testSlotMapNegativeTargetClampsToZero() {
-    SlotMap m;
-    m.append("a"); m.append("b");  // 0,1
-    CHECK(m.reorder("b", -3));      // clamp to 0 -> insert-before a
-    CHECK(m.slotOf("b") == 0);
-    CHECK(m.slotOf("a") == 1);
-}
-
-static void testSlotMapResetDenseSkipsDupesAndEmpties() {
-    SlotMap m;
-    m.resetDense({"a", "", "b", "a", "c"});  // "" and the second "a" dropped
-    CHECK((m.orderedIds() == std::vector<std::string>{"a", "b", "c"}));
-    CHECK(m.slotOf("a") == 0);
-    CHECK(m.slotOf("c") == 2);
-}
-
-static void testSlotMapReconcileDropsStaleAppendsNew() {
-    SlotMap m;
-    m.append("a"); m.append("b"); m.append("c");  // 0,1,2
-    m.reconcile({"a", "c", "d"});  // b left the index (drop), d is new (append)
-    CHECK(m.slotOf("a") == 0);      // kept at its slot
-    CHECK(m.slotOf("c") == 2);      // kept at its slot (gap where b was)
-    CHECK(m.slotOf("b") == -1);     // stale marker dropped
-    CHECK(m.slotOf("d") == 3);      // appended after the frontier
-    CHECK(m.idAt(1).empty());       // b's slot stays empty
-}
-
-static void testSlotMapEqualityAndFromEntries() {
-    SlotMap a;
-    a.append("x"); a.append("y");
-    SlotMap b = SlotMap::fromEntries({{"x", 0}, {"y", 1}});
-    CHECK(a == b);
-    // Defensive repair: duplicate id (first wins), slot conflict (later dropped),
-    // empty id / negative slot dropped.
-    SlotMap c = SlotMap::fromEntries({{"x", 0}, {"x", 5}, {"y", 0}, {"", 9}, {"z", -1}, {"w", 2}});
-    CHECK(c.slotOf("x") == 0);   // first x wins
-    CHECK(c.slotOf("y") == -1);  // slot 0 already taken -> dropped
-    CHECK(c.slotOf("w") == 2);   // valid
-    CHECK(c.slotOf("z") == -1);  // negative slot dropped
-}
+//
+// Pure SlotMap-only unit behaviour (add/remove/query, reorder gap-preservation,
+// resetDense/reconcile, equality/fromEntries, serialize golden literal + round
+// trip) now lives in test_slot_map.cpp (Q-W1 follow-up), extracted per the house
+// every-pure-module-has-a-_tests rule. This file keeps the BankBook-level
+// integration coverage below: reorderSample / reconcileSlots / JSON round-trip
+// WITH a full book.
 
 // --- BankBook L7: JSON round-trip WITH positions -----------------------------
 
@@ -1081,6 +994,7 @@ static void testReplaceSampleInPoolPassesGuard() {
 }
 
 int main() {
+    testSerializeGoldenLiteral();
     testPoolSeededAndDefaults();
     testPoolPrivileges();
     testCreateRenameReorder();
@@ -1117,18 +1031,8 @@ int main() {
     testRemoveAllBanksLatentScope();
     testUpdateSampleInPlace();
 
-    // L7 — SlotMap + ordering/reorder/replace + slot round-trip/migration.
-    testSlotMapDenseAppend();
-    testSlotMapRemoveLeavesGap();
-    testSlotMapAppendAfterGapGoesToFrontier();
-    testSlotMapReorderIntoEmpty();
-    testSlotMapReorderOntoOccupiedInsertsAndShifts();
-    testSlotMapReorderPreservesInteriorGapAboveTarget();
-    testSlotMapReorderUnmappedIsNoOp();
-    testSlotMapNegativeTargetClampsToZero();
-    testSlotMapResetDenseSkipsDupesAndEmpties();
-    testSlotMapReconcileDropsStaleAppendsNew();
-    testSlotMapEqualityAndFromEntries();
+    // L7 — BankBook ordering/reorder/replace + slot round-trip/migration.
+    // (Pure SlotMap-only unit behaviour lives in slot_map_tests.)
     testBankBookSlotsRoundTrip();
     testMigrationDefaultsToInsertionOrderDense();
     testOrderedSampleIdsReconcilesLazily();

tests/test_bank_model.cpp

@@ -104,6 +104,30 @@ static void testFullFieldRoundTrip() {
     }
 }
 
+// Golden byte-literal (Q-W1 T?-05 follow-up): pins the EXACT serialized bytes for
+// a small fixture, not just self-consistent re-serialization — a format drift
+// that round-trips losslessly (e.g. a renamed key both writer and reader agree
+// on) would slip past testFullFieldRoundTrip but not this. The format is frozen
+// as-shipped; the literal below is the captured current output.
+static void testSerializeGoldenLiteral() {
+    BankModel idx;
+    Sample s;
+    s.id = "g1";
+    s.relativePath = "bank/g1.wav";
+    s.contentHash = "hash-g1";
+    CHECK(idx.add(s) == AddResult::Added);
+    CHECK(idx.serialize() ==
+          "{\"version\":1,\"samples\":[{\"id\":\"g1\",\"displayName\":\"\","
+          "\"relativePath\":\"bank/g1.wav\",\"sourceMode\":0,\"sourceRange\":{"
+          "\"startSeconds\":0,\"endSeconds\":0,\"startPpq\":0,\"endPpq\":0},"
+          "\"trackGuids\":[],\"wetDry\":1,\"channelCount\":0,\"sampleRate\":0,"
+          "\"lengthSeconds\":0,\"lengthBeats\":0,\"captureTempo\":0,"
+          "\"captureTimeSigNum\":0,\"captureTimeSigDenom\":0,\"key\":null,"
+          "\"rootNote\":null,\"loop\":null,\"levels\":{\"peakDb\":0,\"rmsDb\":0,"
+          "\"lufs\":0},\"clipped\":false,\"tier\":0,\"contentHash\":\"hash-g1\","
+          "\"provenance\":null,\"createdTimestamp\":0}]}");
+}
+
 static void testDedupByHash() {
     BankModel idx;
     Sample a = fullSample("x");
@@ -551,6 +575,7 @@ static void testSeamFieldsAdditiveInvariant() {
 
 int main() {
     testFullFieldRoundTrip();
+    testSerializeGoldenLiteral();
     testDedupByHash();
     testTierFilterAndMove();
     testRelativePathInvariant();

tests/test_owned_manifest.cpp

@@ -36,6 +36,18 @@ static void testEmptyManifest() {
     CHECK(back->empty());
 }
 
+// Golden byte-literal (Q-W1 follow-up): pins the EXACT serialized bytes for a
+// small fixture (two paths), not just self-consistent re-serialization — a
+// format drift that both writer and reader agree on would slip past the
+// round-trip tests but not this. The format is frozen as-shipped; the literal
+// below is the captured current output.
+static void testSerializeGoldenLiteral() {
+    OwnedFileManifest m;
+    m.add("reasampler_bank/a.wav");
+    m.add("reasampler_bank/b.wav");
+    CHECK(m.serialize() == "{\"owned\":[\"reasampler_bank/a.wav\",\"reasampler_bank/b.wav\"]}");
+}
+
 // --- add / contains / order --------------------------------------------------
 
 static void testAddAndContains() {
@@ -159,6 +171,7 @@ static void testMalformedParse() {
 }
 
 int main() {
+    testSerializeGoldenLiteral();
     testEmptyManifest();
     testAddAndContains();
     testDedupRepeatedAdds();

tests/test_slot_map.cpp

@@ -0,0 +1,228 @@
+// Standalone tests for reasampler::model::SlotMap — no REAPER, no test framework.
+// SlotMap is the L7 gap-preserving display-position carrier for one bank, extracted
+// from bank_book (Q-W1, T4-05). These are the pure SlotMap-only assertions that
+// previously lived inline in test_bank_book.cpp (the L7 "SlotMap unit behaviour"
+// block); test_bank_book.cpp keeps its BankBook-level integration coverage
+// (reorderSample / reconcileSlots / JSON round-trip WITH a full book), this file
+// owns the module's own contract: add/remove/query, reorder gap-preservation,
+// resetDense/reconcile, equality/fromEntries, and the serialize wire shape.
+
+#include "../src/core/model/slot_map.h"
+
+#include <cstdio>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "../src/core/json/json.h"
+
+using namespace reasampler::model;
+namespace json = reasampler::json;
+
+static int g_fail = 0;
+#define CHECK(cond) do { if(!(cond)) { \
+    std::printf("FAIL line %d: %s\n", __LINE__, #cond); ++g_fail; } } while(0)
+
+// --- SlotMap unit behaviour --------------------------------------------------
+
+static void testSlotMapDenseAppend() {
+    SlotMap m;
+    m.append("a");
+    m.append("b");
+    m.append("c");
+    CHECK(m.slotOf("a") == 0);
+    CHECK(m.slotOf("b") == 1);
+    CHECK(m.slotOf("c") == 2);
+    CHECK(m.maxSlot() == 2);
+    CHECK((m.orderedIds() == std::vector<std::string>{"a", "b", "c"}));
+    CHECK(m.idAt(1) == "b");
+    CHECK(m.slotOf("nope") == -1);
+}
+
+static void testSlotMapRemoveLeavesGap() {
+    SlotMap m;
+    m.append("a"); m.append("b"); m.append("c");  // 0,1,2
+    CHECK(m.remove("b"));                          // slot 1 now EMPTY (no re-pack)
+    CHECK(m.slotOf("a") == 0);
+    CHECK(m.slotOf("c") == 2);                     // c did NOT shift down
+    CHECK(m.idAt(1).empty());                      // gap preserved
+    CHECK((m.orderedIds() == std::vector<std::string>{"a", "c"}));
+    CHECK(!m.remove("b"));                         // already gone
+}
+
+static void testSlotMapAppendAfterGapGoesToFrontier() {
+    SlotMap m;
+    m.append("a"); m.append("b"); m.append("c");  // 0,1,2
+    m.remove("a");                                 // slot 0 empty
+    m.append("d");                                 // append goes AFTER last occupied (2) -> 3
+    CHECK(m.slotOf("d") == 3);                      // did NOT fill the slot-0 gap
+    CHECK(m.idAt(0).empty());
+}
+
+static void testSlotMapReorderIntoEmpty() {
+    SlotMap m;
+    m.append("a"); m.append("b"); m.append("c");  // 0,1,2
+    m.remove("b");                                 // slot 1 empty
+    CHECK(m.reorder("c", 1));                       // c -> empty slot 1; its slot 2 empties
+    CHECK(m.slotOf("c") == 1);
+    CHECK(m.idAt(2).empty());
+    CHECK(m.slotOf("a") == 0);                      // untouched
+}
+
+static void testSlotMapReorderOntoOccupiedInsertsAndShifts() {
+    SlotMap m;
+    m.append("a"); m.append("b"); m.append("c"); m.append("d");  // 0,1,2,3
+    CHECK(m.reorder("d", 1));   // d onto occupied slot 1 -> insert-before, shift b,c up
+    CHECK(m.slotOf("a") == 0);  // before the target: unchanged
+    CHECK(m.slotOf("d") == 1);  // took the target slot
+    CHECK(m.slotOf("b") == 2);  // shifted +1
+    CHECK(m.slotOf("c") == 3);  // shifted +1
+    CHECK((m.orderedIds() == std::vector<std::string>{"a", "d", "b", "c"}));
+}
+
+static void testSlotMapReorderPreservesInteriorGapAboveTarget() {
+    SlotMap m;
+    m.append("a"); m.append("b"); m.append("c");  // 0,1,2
+    m.remove("b");                                 // gap at 1: a@0, c@2
+    m.append("d");                                 // d@3
+    CHECK(m.reorder("d", 0));   // d onto occupied slot 0 -> a shifts to 1, c shifts to 3
+    CHECK(m.slotOf("d") == 0);
+    CHECK(m.slotOf("a") == 1);  // shifted from 0 -> 1
+    CHECK(m.slotOf("c") == 3);  // shifted from 2 -> 3 (gap at 2 preserved as a +1 of its own)
+    CHECK(m.idAt(2).empty());   // interior gap above the target survives
+}
+
+static void testSlotMapReorderUnmappedIsNoOp() {
+    SlotMap m;
+    m.append("a");
+    CHECK(!m.reorder("ghost", 0));  // not mapped -> false, no mutation
+    CHECK(m.slotOf("a") == 0);
+}
+
+static void testSlotMapNegativeTargetClampsToZero() {
+    SlotMap m;
+    m.append("a"); m.append("b");  // 0,1
+    CHECK(m.reorder("b", -3));      // clamp to 0 -> insert-before a
+    CHECK(m.slotOf("b") == 0);
+    CHECK(m.slotOf("a") == 1);
+}
+
+static void testSlotMapResetDenseSkipsDupesAndEmpties() {
+    SlotMap m;
+    m.resetDense({"a", "", "b", "a", "c"});  // "" and the second "a" dropped
+    CHECK((m.orderedIds() == std::vector<std::string>{"a", "b", "c"}));
+    CHECK(m.slotOf("a") == 0);
+    CHECK(m.slotOf("c") == 2);
+}
+
+static void testSlotMapReconcileDropsStaleAppendsNew() {
+    SlotMap m;
+    m.append("a"); m.append("b"); m.append("c");  // 0,1,2
+    m.reconcile({"a", "c", "d"});  // b left the index (drop), d is new (append)
+    CHECK(m.slotOf("a") == 0);      // kept at its slot
+    CHECK(m.slotOf("c") == 2);      // kept at its slot (gap where b was)
+    CHECK(m.slotOf("b") == -1);     // stale marker dropped
+    CHECK(m.slotOf("d") == 3);      // appended after the frontier
+    CHECK(m.idAt(1).empty());       // b's slot stays empty
+}
+
+static void testSlotMapEqualityAndFromEntries() {
+    SlotMap a;
+    a.append("x"); a.append("y");
+    SlotMap b = SlotMap::fromEntries({{"x", 0}, {"y", 1}});
+    CHECK(a == b);
+    // Defensive repair: duplicate id (first wins), slot conflict (later dropped),
+    // empty id / negative slot dropped.
+    SlotMap c = SlotMap::fromEntries({{"x", 0}, {"x", 5}, {"y", 0}, {"", 9}, {"z", -1}, {"w", 2}});
+    CHECK(c.slotOf("x") == 0);   // first x wins
+    CHECK(c.slotOf("y") == -1);  // slot 0 already taken -> dropped
+    CHECK(c.slotOf("w") == 2);   // valid
+    CHECK(c.slotOf("z") == -1);  // negative slot dropped
+}
+
+// --- serialize: golden byte-literal + round-trip -----------------------------
+
+// Pins the exact wire shape (an array of {"id":..,"slot":..} objects, ascending
+// slot, no whitespace) so a future format drift is caught here rather than only
+// as a downstream bank_book diff. Mirrors the pre-extraction bank_book writer
+// byte-for-byte (core/json emit helpers are shared, not reimplemented).
+static void testSlotMapSerializeGoldenLiteral() {
+    SlotMap empty;
+    CHECK(empty.serialize() == "[]");
+
+    SlotMap m;
+    m.append("a");
+    m.append("b");
+    CHECK(m.serialize() == "[{\"id\":\"a\",\"slot\":0},{\"id\":\"b\",\"slot\":1}]");
+}
+
+// A local mirror of bank_book's private parseSlots (the "slots" array grammar):
+// [{id, slot}, ...]. slot_map.cpp itself only emits — JSON parsing is a consumer
+// concern (see slot_map.h) — so the round-trip proof below parses the emitted
+// text back into pairs the same way bank_book does, then rebuilds via
+// SlotMap::fromEntries and checks equality against the original.
+static bool parseSlotsArray(json::Reader& r, std::vector<std::pair<std::string, int>>& out) {
+    out.clear();
+    if (!r.consume('[')) return false;
+    r.skipWs();
+    if (r.consume(']')) return true;  // empty array
+    do {
+        if (!r.consume('{')) return false;
+        std::string id;
+        int slot = 0;
+        bool haveId = false, haveSlot = false;
+        do {
+            std::string k;
+            if (!r.parseKey(k)) return false;
+            if (k == "id") { if (!r.parseString(id)) return false; haveId = true; }
+            else if (k == "slot") { if (!r.parseInt(slot)) return false; haveSlot = true; }
+            else { if (!r.skipValue()) return false; }
+        } while (r.consume(','));
+        if (!r.consume('}')) return false;
+        if (!haveId || !haveSlot) return false;
+        out.emplace_back(std::move(id), slot);
+    } while (r.consume(','));
+    return r.consume(']');
+}
+
+static void testSlotMapSerializeRoundTrip() {
+    SlotMap m;
+    m.append("a"); m.append("b"); m.append("c");
+    m.remove("b");        // leave a gap: a@0, c@2
+    m.append("d");        // d@3
+
+    const std::string blob = m.serialize();
+    json::Reader r(blob);
+    std::vector<std::pair<std::string, int>> pairs;
+    CHECK(parseSlotsArray(r, pairs));
+
+    SlotMap round = SlotMap::fromEntries(pairs);
+    CHECK(round == m);
+    CHECK(round.slotOf("a") == 0);
+    CHECK(round.idAt(1).empty());  // gap survives the round trip
+    CHECK(round.slotOf("c") == 2);
+    CHECK(round.slotOf("d") == 3);
+}
+
+int main() {
+    testSlotMapDenseAppend();
+    testSlotMapRemoveLeavesGap();
+    testSlotMapAppendAfterGapGoesToFrontier();
+    testSlotMapReorderIntoEmpty();
+    testSlotMapReorderOntoOccupiedInsertsAndShifts();
+    testSlotMapReorderPreservesInteriorGapAboveTarget();
+    testSlotMapReorderUnmappedIsNoOp();
+    testSlotMapNegativeTargetClampsToZero();
+    testSlotMapResetDenseSkipsDupesAndEmpties();
+    testSlotMapReconcileDropsStaleAppendsNew();
+    testSlotMapEqualityAndFromEntries();
+    testSlotMapSerializeGoldenLiteral();
+    testSlotMapSerializeRoundTrip();
+
+    if (g_fail == 0) {
+        std::printf("slot_map_tests: all passed\n");
+        return 0;
+    }
+    std::printf("slot_map_tests: %d failure(s)\n", g_fail);
+    return 1;
+}

tests/test_view_mode_model.cpp

@@ -56,6 +56,20 @@ static int flagValue(const TrackPlan& p, Flag f) {
     return -999;  // sentinel: flag absent
 }
 
+// Golden byte-literal (Q-W1 follow-up): pins the EXACT serialized bytes for the
+// default-seeded model (Arrange + Design, no membership), not just self-
+// consistent re-serialization — a format drift that both writer and reader
+// agree on would slip past the round-trip tests but not this. The format is
+// frozen as-shipped; the literal below is the captured current output.
+static void testSerializeGoldenLiteral() {
+    ViewModeModel vm;
+    CHECK(vm.serialize() ==
+          "{\"version\":1,\"activeMode\":\"arrange\",\"modes\":[{\"id\":\"arrange\","
+          "\"displayName\":\"Arrange\",\"ordinal\":0},{\"id\":\"design\","
+          "\"displayName\":\"Design\",\"ordinal\":1}],\"membership\":[],"
+          "\"snapshots\":[],\"lanes\":[]}");
+}
+
 // -- 1. N-mode proven --------------------------------------------------------
 
 static void testNModeRegistryAndMembership() {
@@ -1787,6 +1801,7 @@ static void testLaneMalformedJson() {
 }
 
 int main() {
+    testSerializeGoldenLiteral();
     testNModeRegistryAndMembership();
     testParentDerivationMultiMode();
     testParentOwnMembershipVisibility();