feat: add M6 insert — place selected bank sample at edit cursor

InsertMedia-driven placement reading the bank panel selection, undo-wrapped.
Native length by default; conform-to-tempo is an explicit second action, never
a silent stretch. Pure mode-bit logic (insert_plan) unit-tested.

CMakeLists.txt

@@ -65,6 +65,15 @@ add_library(view_tree STATIC src/view_tree.cpp)
 target_include_directories(view_tree PUBLIC src)
 target_link_libraries(view_tree PUBLIC view_mode_model)
 
+# ---------------------------------------------------------------------------
+# 2e) Pure insert_plan library — NO REAPER, NO SWELL. The InsertMedia `mode`
+#     bitmask arithmetic behind the `insert` shell (M6). Split out so the
+#     load-bearing bit computation (no silent stretch, opt-in conform) is
+#     unit-tested outside the DAW; the InsertMedia call itself is DAW-verified.
+# ---------------------------------------------------------------------------
+add_library(insert_plan STATIC src/insert_plan.cpp)
+target_include_directories(insert_plan PUBLIC src)
+
 # ---------------------------------------------------------------------------
 # 3) Standalone tests for the pure modules (run without launching REAPER).
 # ---------------------------------------------------------------------------
@@ -93,6 +102,10 @@ add_executable(view_tree_tests tests/test_view_tree.cpp)
 target_link_libraries(view_tree_tests PRIVATE view_tree)
 add_test(NAME view_tree_tests COMMAND view_tree_tests)
 
+add_executable(insert_plan_tests tests/test_insert_plan.cpp)
+target_link_libraries(insert_plan_tests PRIVATE insert_plan)
+add_test(NAME insert_plan_tests COMMAND insert_plan_tests)
+
 # ---------------------------------------------------------------------------
 # 4) The REAPER extension — a loadable module (dlopen'd by REAPER, not linked).
 # ---------------------------------------------------------------------------
@@ -112,6 +125,8 @@ add_library(reaper_reasampler MODULE
     src/capture.cpp
     src/persist.cpp
     src/bank_panel.cpp
+    src/insert.cpp
+    src/insert_plan.cpp
     ${LICE_SRC}
     src/view_mode_model.cpp
     src/view_tree.cpp
@@ -119,7 +134,7 @@ 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 view_mode_model)
+target_link_libraries(reaper_reasampler PRIVATE bank_model capture_paths peaks bank_grid view_mode_model insert_plan)
 target_include_directories(reaper_reasampler PRIVATE ${SDK_INC} ${WDL_INC})
 set_target_properties(reaper_reasampler PROPERTIES PREFIX "" OUTPUT_NAME "reaper_reasampler")