tests: coverage round 6 (sequence, generators, renderer misc, multicam/serializer)

- sequence_test: Sequence/TrackList track wiring, length propagation,
  context/cache indexing, signals
- node_generator_test: MatrixGenerator transform math, Shape/Solid/
  Noise/Polygon shader jobs, TextGeneratorV3 formatting
- render_misc_test: DynamicRenderer paths, Renderer texture/shader
  caches via stub renderer, color-management blit plumbing,
  PreviewAutoCacher scheduling
- multicam_serializer_test: MultiCamNode sources/angles/grids,
  FootageDescription round trips, ProjectSerializer file and version
  handling

tests/gtest/CMakeLists.txt

@@ -67,6 +67,10 @@ add_executable(olive-gtest
   node_time_test.cpp
   node_color_test.cpp
   plugin_node_test.cpp
+  sequence_test.cpp
+  node_generator_test.cpp
+  render_misc_test.cpp
+  multicam_serializer_test.cpp
   timeline_marker_test.cpp
   undo_stack_test.cpp
   plugin_support_test.cpp