R8: finish app/ pure C ABI migration (P3-P9) and make OTIO required

- app/ no longer includes engine C++ headers nor holds engine C++ types:
  engine access goes through the oakengine C ABI plus C++ wrappers
  (oakutil/oaknode.h, oakutil/oakvideo.h) and app-local mirror types
  (tooltypes, trackreferencehandle, timelinecommonapp, keyframetypes,
  subtitleapp, serializedlayoutinfoapp, nodevaluehandle, sliderdisplaytypeapp)
- engine: new C ABI functions for block/track/clip/transition navigation
  and predicates, links, caches, waveform/playback, disk folder,
  sequence_track_list, node_free, footage_is_valid, block_get_track,
  get_brush; loadotio/saveotio ported to the current engine API
- OTIO is now a required dependency: CI and CD build it on every
  platform, FindOpenTimelineIO fixed for OTIO 0.16/0.19 (the old deps
  include requirement silently disabled OTIO everywhere), runtime
  libraries are bundled into packages and copied next to macOS binaries
  (oak_copy_otio_runtime)
- fix ProjectViewModel drag&drop mime read/write size mismatch (segfault)
- unify color label naming (k_olive -> "Oak") in the app-side mirror
- docs: OTIO required, FFmpeg minimum corrected to 6.0 (en/zh)
- gtest suite: 1925 passed, 0 failed

app/CMakeLists.txt

@@ -22,6 +22,7 @@ set(OLIVE_SOURCES
         engineeventbridge.h
         engineeventbridge.cpp
         common/colorcodingapp.h
+        common/colorcodingapp.cpp
         common/nodevaluehandle.h
 )
 
@@ -86,6 +87,10 @@ add_executable(olive-editor
         $<TARGET_OBJECTS:olive-version-obj>
 )
 
+if (COMMAND oak_copy_otio_runtime)
+  oak_copy_otio_runtime(olive-editor)
+endif()
+
 target_link_libraries(olive-editor PUBLIC OfxHost)
 add_dependencies(olive-editor oakgl-cabi-check)
 if (OAK_ENABLE_DYNAMIC_RENDER_BACKEND)