feat(capture): M8 async realtime-record backend (master scope)

Timer-driven realtime capture behind ICaptureBackend (begin/tick/abort via
OnTimer, non-blocking). Records master into a hidden temp track, moved to the
bank non-destructively with idempotent restore across every terminal path.
Pure phase machine unit-tested. Track/item deferred; realtime is non-deterministic.

CMakeLists.txt

@@ -96,6 +96,18 @@ add_library(render_settings STATIC src/render_settings.cpp)
 target_include_directories(render_settings PUBLIC src)
 target_link_libraries(render_settings PUBLIC bank_model)
 
+# ---------------------------------------------------------------------------
+# 2g) Pure realtime_record library — NO REAPER, NO SWELL. The M8 realtime-record
+#     logic: capture scope + FX-tap point -> I_RECMODE / I_RECMODE_FLAGS values,
+#     wet/dry -> tap point, and the recorded-file -> Sample mapping. Split out so
+#     the fiddly record-mode bit values + Sample population are unit-tested outside
+#     the DAW; the transport/temp-track/send/file-move recipe stays in capture.cpp.
+#     Depends on bank_model for the pure Sample / SourceMode types.
+# ---------------------------------------------------------------------------
+add_library(realtime_record STATIC src/realtime_record.cpp)
+target_include_directories(realtime_record PUBLIC src)
+target_link_libraries(realtime_record PUBLIC bank_model)
+
 # ---------------------------------------------------------------------------
 # 3) Standalone tests for the pure modules (run without launching REAPER).
 # ---------------------------------------------------------------------------
@@ -136,6 +148,10 @@ add_executable(render_settings_tests tests/test_render_settings.cpp)
 target_link_libraries(render_settings_tests PRIVATE render_settings)
 add_test(NAME render_settings_tests COMMAND render_settings_tests)
 
+add_executable(realtime_record_tests tests/test_realtime_record.cpp)
+target_link_libraries(realtime_record_tests PRIVATE realtime_record)
+add_test(NAME realtime_record_tests COMMAND realtime_record_tests)
+
 # ---------------------------------------------------------------------------
 # 4) The REAPER extension — a loadable module (dlopen'd by REAPER, not linked).
 # ---------------------------------------------------------------------------
@@ -153,6 +169,8 @@ set(LICE_SRC
 add_library(reaper_reasampler MODULE
     src/main.cpp
     src/capture.cpp
+    src/capture_realtime.cpp
+    src/realtime_record.cpp
     src/persist.cpp
     src/bank_panel.cpp
     src/mode_switch.cpp
@@ -165,7 +183,7 @@ add_library(reaper_reasampler MODULE
     src/track_guid.cpp
     src/actions.cpp
 )
-target_link_libraries(reaper_reasampler PRIVATE bank_model capture_paths peaks bank_grid mode_switch view_mode_model insert_plan render_settings)
+target_link_libraries(reaper_reasampler PRIVATE bank_model capture_paths peaks bank_grid mode_switch view_mode_model insert_plan render_settings realtime_record)
 target_include_directories(reaper_reasampler PRIVATE ${SDK_INC} ${WDL_INC})
 set_target_properties(reaper_reasampler PROPERTIES PREFIX "" OUTPUT_NAME "reaper_reasampler")