Retire MPE scaffold; stand up reaper_reasampler pure-core skeleton

Rename CMake project/module to reaper_reasampler, delete mpe_model/mpe_view,
add minimal pure bank_model lib + placeholder CTest. main.cpp loads, logs to
console, keeps the action-registration seam commented with the forever-stable
CEREBELLUM_REASAMPLER_ action-id prefix.

CMakeLists.txt

@@ -0,0 +1,62 @@
+cmake_minimum_required(VERSION 3.19)
+project(reaper_reasampler LANGUAGES CXX)
+
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+
+# ---------------------------------------------------------------------------
+# Vendored dependencies — add as git submodules (see README):
+#   git submodule add https://github.com/justinfrankel/reaper-sdk vendor/reaper-sdk
+#   git submodule add https://github.com/justinfrankel/WDL        vendor/WDL
+# ---------------------------------------------------------------------------
+set(SDK_INC ${CMAKE_CURRENT_SOURCE_DIR}/vendor/reaper-sdk/sdk)
+set(WDL_INC ${CMAKE_CURRENT_SOURCE_DIR}/vendor/WDL/WDL)
+set(SWELL   ${WDL_INC}/swell)
+
+# ---------------------------------------------------------------------------
+# 1) Pure model library — NO REAPER, NO SWELL. Builds & tests anywhere.
+#    The sampler's heart: Sample metadata + BankIndex (Milestone 1).
+# ---------------------------------------------------------------------------
+add_library(bank_model STATIC src/bank_model.cpp)
+target_include_directories(bank_model PUBLIC src)
+
+# ---------------------------------------------------------------------------
+# 2) Standalone tests for the model (run without launching REAPER).
+# ---------------------------------------------------------------------------
+enable_testing()
+add_executable(bank_model_tests tests/test_bank_model.cpp)
+target_link_libraries(bank_model_tests PRIVATE bank_model)
+add_test(NAME bank_model_tests COMMAND bank_model_tests)
+
+# ---------------------------------------------------------------------------
+# 3) The REAPER extension — a loadable module (dlopen'd by REAPER, not linked).
+# ---------------------------------------------------------------------------
+add_library(reaper_reasampler MODULE
+    src/main.cpp
+)
+target_link_libraries(reaper_reasampler PRIVATE bank_model)
+target_include_directories(reaper_reasampler PRIVATE ${SDK_INC} ${WDL_INC})
+set_target_properties(reaper_reasampler PROPERTIES PREFIX "" OUTPUT_NAME "reaper_reasampler")
+
+if(WIN32)
+    # Native Win32. REAPER provides nothing extra to link.
+    # Dialog resources return with the docked bank_panel (Milestone 5).
+
+elseif(APPLE)
+    # macOS: use REAPER's OWN SWELL at runtime via the modstub.
+    # Do NOT build full SWELL. SWELL_PROVIDED_BY_APP routes calls to the host.
+    target_sources(reaper_reasampler PRIVATE ${SWELL}/swell-modstub.mm)
+    target_compile_definitions(reaper_reasampler PRIVATE SWELL_PROVIDED_BY_APP)
+    target_link_libraries(reaper_reasampler PRIVATE "-framework AppKit")
+    set_target_properties(reaper_reasampler PROPERTIES SUFFIX ".dylib")
+    # Dialog: run SWELL resgen once (see README) and add the generated source.
+
+else()
+    # Linux: REAPER's libSwell.so is used at runtime via the generic modstub.
+    # With SWELL_PROVIDED_BY_APP you can drop pkg-config / -lX11 entirely.
+    target_sources(reaper_reasampler PRIVATE ${SWELL}/swell-modstub-generic.cpp)
+    target_compile_definitions(reaper_reasampler PRIVATE SWELL_PROVIDED_BY_APP)
+    set_target_properties(reaper_reasampler PROPERTIES SUFFIX ".so")
+    # Dialog: run SWELL resgen once (see README) and add the generated source.
+endif()

src/bank_model.cpp

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+#include "bank_model.h"
+
+namespace reasampler {
+
+int bankModelVersion()
+{
+    return 1;
+}
+
+} // namespace reasampler

src/bank_model.h

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+#pragma once
+// bank_model — the HEART of ReaSampler, deliberately free of any REAPER type so
+// it compiles and unit-tests OUTSIDE the DAW. It owns the per-project sample
+// bank: the `Sample` metadata struct and the `BankIndex` (add / remove / query /
+// tier moves / dedup-by-hash + JSON round-trip).
+//
+// Milestone 0 placeholder: this is a minimal compiling stub sufficient to stand
+// up the pure static lib and its CTest. The full data model (Sample field set,
+// BankIndex operations, JSON) is Milestone 1 — see PLAN.md / CONTEXT.md §Data model.
+
+namespace reasampler {
+
+// M0 placeholder — replaced by the real `Sample` / `BankIndex` in Milestone 1.
+// Returns the on-disk schema version the bank_model serializes to.
+int bankModelVersion();
+
+} // namespace reasampler

src/main.cpp

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+// main.cpp — the SINGLE translation unit that OWNS the REAPER API pointers.
+//
+// This file is the entire contract between REAPER and the extension:
+//   * At startup REAPER scans UserPlugins/ for reaper_*.dll|dylib|so and
+//     dlopen()s each one, then looks up ONE exported symbol: ReaperPluginEntry
+//     (that name is produced by the REAPER_PLUGIN_ENTRYPOINT macro).
+//   * REAPER calls it, handing over `rec` — a small dispatch struct.
+//       - rec->GetFunc(name)      resolves any REAPER API function to a pointer
+//       - rec->Register(what,ptr) plugs OUR callbacks into REAPER
+//   * REAPERAPI_LoadAPI(rec->GetFunc) walks reaper_plugin_functions.h and
+//     fills in every global function pointer (ShowConsoleMsg, InsertMedia...).
+//
+// Exactly ONE .cpp defines REAPERAPI_IMPLEMENT (this one) — that allocates
+// storage for those global pointers. Every other .cpp includes
+// reaper_plugin_functions.h WITHOUT the define and gets `extern` declarations.
+
+#define REAPERAPI_IMPLEMENT
+#include "reaper_plugin.h"
+#include "reaper_plugin_functions.h"
+
+// Persistent action-id prefix for the ReaSampler action family.
+// Every bindable action (capture / insert / slot / verify) mints its command id
+// from a string beginning with this prefix, e.g. "CEREBELLUM_REASAMPLER_CAPTURE_MASTER".
+// FOREVER-STABLE once shipped: user keybindings key off these strings, so the
+// prefix and any minted id must never change after release.
+#define REASAMPLER_ACTION_PREFIX "CEREBELLUM_REASAMPLER_"
+
+// Globals other files reference via `extern`.
+REAPER_PLUGIN_HINSTANCE g_hInst = nullptr;  // this module's instance handle
+reaper_plugin_info_t*   g_rec   = nullptr;  // REAPER's dispatch struct
+
+// ---- Action registration seam (reusable pattern, no action wired yet) ------
+// The capture/insert/slot action family (PLAN.md M3+) reinstates the pattern
+// below. Kept as a commented template so the shape is not re-derived each time.
+//
+// static int g_cmdCaptureMaster = 0;
+//
+// // REAPER calls this for EVERY action fired anywhere; claim only your own id,
+// // return false otherwise so REAPER keeps looking.
+// static bool OnHookCommand(int command, int /*flag*/)
+// {
+//     if (command == 0) return false;
+//     if (command == g_cmdCaptureMaster) { /* route to capture module */ return true; }
+//     return false;
+// }
+//
+// Registration, inside the load branch below:
+//   1) g_cmdCaptureMaster =
+//          rec->Register("command_id", (void*)(REASAMPLER_ACTION_PREFIX "CAPTURE_MASTER"));
+//   2) static gaccel_register_t sAccel{};
+//      sAccel.accel.cmd = g_cmdCaptureMaster;
+//      sAccel.desc      = "ReaSampler: capture master mix";
+//      rec->Register("gaccel", (void*)&sAccel);
+//   3) rec->Register("hookcommand", (void*)&OnHookCommand);
+// On unload (rec == nullptr), mirror-unregister with the same strings prefixed '-'.
+
+extern "C" REAPER_PLUGIN_DLL_EXPORT int REAPER_PLUGIN_ENTRYPOINT(
+    REAPER_PLUGIN_HINSTANCE hInstance, reaper_plugin_info_t* rec)
+{
+    if (!rec)
+    {
+        // rec == nullptr  =>  REAPER is UNLOADING us. Mirror-unregister every
+        // callback here (same strings prefixed with '-') once actions are wired.
+        g_rec = nullptr;
+        return 0;
+    }
+
+    // ABI guard: the struct layout we compiled against must match this REAPER.
+    if (rec->caller_version != REAPER_PLUGIN_VERSION)
+        return 0;
+
+    // Resolve every REAPER API function pointer. Returns the number that FAILED
+    // to load; 0 == success. Non-zero usually means REAPER is older than our SDK.
+    if (REAPERAPI_LoadAPI(rec->GetFunc) != 0)
+        return 0;
+
+    g_hInst = hInstance;
+    g_rec   = rec;
+
+    ShowConsoleMsg("ReaSampler loaded.\n");
+
+    return 1;  // success — REAPER keeps us loaded
+}

tests/test_bank_model.cpp

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+// Standalone tests for reasampler::bank_model — no REAPER, no test framework.
+// This is the point of splitting the model out: iterate the hard logic here with
+// a fast build/run loop instead of restarting REAPER.
+//
+// Milestone 0 placeholder: a single assertion proving the pure lib links and
+// runs under CTest. The real round-trip / dedup / tier / relative-path tests
+// arrive with the Milestone 1 data model (see TODO.md, PLAN.md).
+
+#include "../src/bank_model.h"
+#include <cstdio>
+
+using namespace reasampler;
+
+static int g_fail = 0;
+#define CHECK(cond) do { if(!(cond)) { \
+    std::printf("FAIL line %d: %s\n", __LINE__, #cond); ++g_fail; } } while(0)
+
+int main()
+{
+    CHECK(bankModelVersion() == 1);
+
+    if (g_fail == 0) std::printf("All tests passed.\n");
+    return g_fail ? 1 : 0;
+}