Q-W5: persist → session/ext_state_io/prune_fs (deletion authority concentrated); one GetProjExtState grow-loop in bridge_marshal (T2-04, ×3 rewired); bank_book JSON codec → bank_book_json via private static nameKey; persist.h stays umbrella. 61/61 green.

src/shell/persist/ext_state_io.h

@@ -0,0 +1,59 @@
+#pragma once
+// ext_state_io — the ext-state ↔ JSON serialization half of the persist seam
+// (Q-W5 split of the former persist god-TU; session.h holds the ReaSamplerSession
+// lifecycle, prune_fs.cpp the prune scan + the single file-deletion authority).
+// This header owns the persist-side key spellings and the channel-derived
+// namespace accessor; the TU (ext_state_io.cpp) implements the session's
+// save/load/assignment-request bridge plus the GUID minting and bank-folder
+// relocation helpers the poll executes.
+//
+// The ext-state namespace + the WIRE-SHARED key names are the contract between this
+// extension (writer) and the VST3 instrument (reader), so they live in ext_keys.h
+// (pure, REAPER-free) and are included here — not duplicated. The namespace is
+// CHANNEL-DERIVED (Phase V, V4): ext_keys.h's kProjExtNamespace / this projExtNamespace()
+// both delegate to app_version's extStateNamespace() — "reasampler" on stable (byte-
+// identical to the pre-V4 build) or "reasampler_beta" on the isolated beta build. Both
+// artifacts read the ONE app_version symbol, so the instrument reads exactly the namespace
+// the extension writes, per channel. Beta reads/writes ONLY its own namespace — a project
+// saved by stable shows empty/default state in beta and vice versa; that isolation is the
+// accepted V4 safety property (no cross-namespace read, migration, or fallback), not a bug.
+// The per-key semantics persist relies on (spellings owned by ext_keys.h):
+//   * kProjExtBanksKey  : the whole serialized BankBook (pool + named banks).
+//     AUTHORITATIVE going forward; the VST reads this key to see the live bank.
+//   * kProjExtIndexKey  : RETIRED legacy single-bank key. No longer WRITTEN (cleared
+//     on save); READ once on load to migrate a legacy project into the pool.
+//   * kProjExtViewKey   : the Design-View ViewModeModel JSON.
+//   * kProjExtTailKey   : the docked panel's TailSetting JSON.
+//   * kProjExtGuidKey   : the per-project minted GUID (content-based identity; poll()
+//     tells a Save-As from a recycled-pointer project switch by it).
+// All are FOREVER-STABLE once shipped: changing any strands every already-saved
+// project's stored state under that key.
+
+#include "core/version/app_version.h"
+#include "ext_keys.h"
+
+namespace reasampler {
+
+// The accessor form of the namespace: ext_keys.h's kProjExtNamespace is the value; this
+// is the const char* the SetProjExtState/GetProjExtState calls pass. Kept as an
+// accessor (not a literal) because the string is channel-derived at build time.
+inline const char* projExtNamespace() { return version::extStateNamespace().c_str(); }
+
+// The two EXTENSION-ONLY keys — NOT part of the VST wire contract (the instrument
+// reads only banks/view/tail/guid), so they stay here rather than in ext_keys.h:
+//
+// owned_files — the owned-file manifest JSON (project-relative files the capture path
+// itself created; Phase B B-cap seam, consumed by Phase R prune to tell the bank system's
+// own orphans from hand-dropped files). A SIBLING key alongside banks/view/tail — NOT
+// folded into `banks`, so it stays decoupled from membership. FOREVER-STABLE: changing it
+// strands every saved project's ownership record (prune falls back to an empty manifest —
+// graceful, but the attribution safety net is lost until the next capture rebuilds it).
+inline constexpr const char* kProjExtOwnedKey = "owned_files";
+
+// version — the ReaSampler version that last WROTE this project (Phase V, V1). Written on
+// every save, so every saved .rpp records which build produced its state — the seam a
+// future within-channel forward migration keys off. An absent key is the explicit
+// pre-versioning case, read silently, never an error. FOREVER-STABLE key string.
+inline constexpr const char* kProjExtVersionKey = "version";
+
+}  // namespace reasampler