Expand Google Test coverage across core subsystems

Add and extend unit tests for:
- Task manager (failed tasks, progress signals, multiple tasks)
- Undo stack (multiple undo/redo, push-after-undo, clear, multi-command)
- Config defaults and graphics backend string conversion
- Node keyframe serialization and default state
- Node value string round-trips and table operations
- Node globals and project settings/serialization
- Timeline coordinate, workarea, and marker commands
- Color LUT processor and OCIO transform handling
- Common utilities (range, file functions, Qt helpers, XML utils)
- Render enums (loop mode, alpha association)
- Shader resource availability
- Module smoke tests for Tool and HumanStrings

All tests pass including RenderWorkerFootage GPU worker tests after
rebuilding the stale olive-render-worker binary.

tests/gtest/CMakeLists.txt

@@ -2,6 +2,9 @@ add_executable(olive-gtest
   main.cpp
   common_current_test.cpp
   common_xmlutils_test.cpp
+  common_range_test.cpp
+  common_filefunctions_test.cpp
+  common_qtutils_test.cpp
   config_test.cpp
   audio_level_meter_test.cpp
   audio_synchronizer_test.cpp
@@ -10,12 +13,16 @@ add_executable(olive-gtest
   node_value_test.cpp
   node_keyframe_test.cpp
   node_serialization_test.cpp
+  node_globals_test.cpp
+  node_project_test.cpp
   render_videoparams_test.cpp
   render_videoparams_branch_test.cpp
   render_audioparams_test.cpp
   render_audioparams_branch_test.cpp
   render_sampleformat_test.cpp
   render_pixelformat_test.cpp
+  render_loopmode_test.cpp
+  render_alphaassoc_test.cpp
   render_ipc_test.cpp
   render_ticket_test.cpp
   render_worker_footage_test.cpp