feat(version): single-source semver, ext-state stamp, show-version action

Version "0.9.01" sourced once from CMake via configure_file'd header; pure
app_version module (parse/compare/classify) with CTest. Stamp rides the persist
save seam under "reasampler"/"version"; absent stamp reads as pre-versioning.
On-demand "show version" action, no startup print.

src/main.cpp

@@ -24,6 +24,7 @@
 #include <vector>
 
 #include "actions.h"
+#include "app_version.h"
 #include "bank_model.h"
 #include "bank_panel.h"
 #include "capture.h"
@@ -109,6 +110,13 @@ static int g_cmdCaptureTrackRealtime = 0;
 // the transport-stop. No-op (with a note) when nothing is in flight.
 static int g_cmdCancelRealtime = 0;
 
+// Command id for the Phase V "show version" action. FOREVER-STABLE string. On demand
+// ONLY — prints the CMake-sourced version string to the console when fired. This is the
+// SOLE new console output the versioning wave adds; there is no unconditional startup
+// version print (routine console chatter was deliberately removed — it pops the console
+// window). The user copies this line into a bug report.
+static int g_cmdShowVersion = 0;
+
 // The persistence session (M4): owns the in-memory BankIndex and bridges it to
 // project ext state. A timer tick drives g_session.poll() to detect project
 // load / Save-As; capture adds Samples to g_session.bank() — which (B2) resolves to
@@ -771,6 +779,12 @@ static bool OnHookCommand(int command, int /*flag*/)
     if (command == g_cmdInsertSelectedConform)   { RunInsertSelected(true);  return true; }
     if (command == g_cmdCaptureTrackRealtime)    { RunCaptureRealtimeTrack(); return true; }
     if (command == g_cmdCancelRealtime)          { RunCancelRealtime(); return true; }
+    if (command == g_cmdShowVersion)
+    {
+        // On-demand version readout — the ONLY version output on any path.
+        ShowConsoleMsg(("ReaSampler " + reasampler::appVersion() + "\n").c_str());
+        return true;
+    }
     // Design View action family (D4). Claims only its own ids; returns false for the
     // rest so this hook keeps looking (per the contract).
     if (reasampler::designViewHandleCommand(command)) return true;
@@ -795,6 +809,7 @@ static gaccel_register_t g_accelInsertSelected{};
 static gaccel_register_t g_accelInsertSelectedConform{};
 static gaccel_register_t g_accelCaptureTrackRealtime{};
 static gaccel_register_t g_accelCancelRealtime{};
+static gaccel_register_t g_accelShowVersion{};
 
 extern "C" REAPER_PLUGIN_DLL_EXPORT int REAPER_PLUGIN_ENTRYPOINT(
     REAPER_PLUGIN_HINSTANCE hInstance, reaper_plugin_info_t* rec)
@@ -826,6 +841,9 @@ extern "C" REAPER_PLUGIN_DLL_EXPORT int REAPER_PLUGIN_ENTRYPOINT(
             reasampler::designViewUnregisterActions(g_rec);
             // Tear down the multi-bank action family (B3) — same mirror-unregister.
             reasampler::bankUnregisterActions(g_rec);
+            g_rec->Register("-gaccel", (void*)&g_accelShowVersion);
+            g_rec->Register("-command_id",
+                            (void*)(REASAMPLER_ACTION_PREFIX "SHOW_VERSION"));
             g_rec->Register("-gaccel", (void*)&g_accelCancelRealtime);
             g_rec->Register("-command_id",
                             (void*)(REASAMPLER_ACTION_PREFIX "CANCEL_REALTIME_CAPTURE"));
@@ -969,6 +987,19 @@ extern "C" REAPER_PLUGIN_DLL_EXPORT int REAPER_PLUGIN_ENTRYPOINT(
         rec->Register("gaccel", (void*)&g_accelCancelRealtime);
     }
 
+    // Register the Phase V "show version" action (command_id -> gaccel -> hookcommand).
+    // On-demand only — prints the CMake-sourced version to the console when fired; no
+    // startup print. FOREVER-STABLE id string.
+    g_cmdShowVersion = rec->Register(
+        "command_id",
+        (void*)(REASAMPLER_ACTION_PREFIX "SHOW_VERSION"));
+    if (g_cmdShowVersion)
+    {
+        g_accelShowVersion.accel.cmd = g_cmdShowVersion;
+        g_accelShowVersion.desc      = "ReaSampler: show version";
+        rec->Register("gaccel", (void*)&g_accelShowVersion);
+    }
+
     // Register the Design View action family (D4): toggle/activate mode, tag/untag/
     // show-both selected tracks. Each mints its own command_id + gaccel; the single
     // hookcommand below routes them via designViewHandleCommand. Registered before