fix: bug-fix sweep across node, audio, render, plugin subsystems

Node core:
- MathNode/TrigonometryNode combo strings realigned with Operation enums
- mathbase scalar/vector operand pick no longer uses bitwise type checks
- NodeSetPositionAndDependenciesRecursively moves dependencies again
- RemoveAllKeyframes undo actually restores keyframes
- NodeGroup GetInputName null-deref guard, passthrough ids use input id
- NodeValueTable::Has is an exact type match; tag fallback only for
  empty tags; kStrCombo/kPushButton get data type names
- delete_all_keyframes no longer loops forever on unparented keyframes;
  keyframe-load failures propagate; rational interpolation falls back to
  double; OpacityEffect no longer leaks its internal MathNode

Audio/footage:
- AudioVisualWaveform: GetSummaryFromTime underflow OOB read, TrimIn
  prepend length bookkeeping, OverwriteSums source channel indexing
- PanNode inserts the pan value into the sample job (keyframed pan
  works); OutputParamsChanged is emitted on device change; PortAudio
  device indices are validated before Pa_GetDeviceInfo
- Footage: AdjustTimeByLoopMode no longer hangs/UBs on degenerate
  lengths, GetStreamIndex bounds-checked, CheckFootage clears stale
  state on missing files, failed probes are not cached,
  FootageDescription::Load requires its own root element

Render/track:
- ViewerOutput pushes the tagged samples value; TrackList disconnects
  the track-height lambda; GetTrackFromReference validity check
- RenderManager dummy backend: null-initialized threads, guarded
  decoder-cache/timer paths; Renderer::Destroy releases color cache
  shaders/textures; unknown dynamic backends no longer alias to oakgl
- SharedMemoryRegion POSIX attach validates segment size; ReadMessage
  skips blank lines instead of failing; GC counter clamped;
  IsRenderingCustomRange implemented; TimeOffsetNode gets a true
  inverse OutputTimeAdjustment; zero-speed clips return the held frame

Plugin/nodes:
- OliveClip: stored default region of definition is honored, on-demand
  images are cached; OliveHost sets host identity properties and logs
  instead of showing modal dialogs offscreen; Plugin.h dead decls gone
- DespillNode guards graph-less use with Rec.709 fallback; description
  typos fixed (despill, swirl); mosaic applies when only one axis
  matches; Windows-only Project filename separator test fixed

tests/gtest/plugin_support_clip_test.cpp

@@ -75,19 +75,24 @@ TEST(PluginSupportClip, GetImageClampsBoundsAndCachesOutput)
 	EXPECT_EQ(image, image_again);
 }
 
-TEST(PluginSupportClip, GetImageReturnsNewImageForNonOutput)
+TEST(PluginSupportClip, GetImageCachesImageForNonOutput)
 {
 	OFX::Host::ImageEffect::ClipDescriptor desc("Source");
 	olive::VideoParams params =
 		MakeParams(64, 64, olive::core::PixelFormat::U8, 4, false);
 	olive::plugin::OliveClipInstance clip(nullptr, desc, params);
 
+	EXPECT_FALSE(clip.getConnected());
+
 	OFX::Host::ImageEffect::Image *first = clip.getImage(0.0, nullptr);
 	OFX::Host::ImageEffect::Image *second = clip.getImage(0.0, nullptr);
 
 	EXPECT_NE(first, nullptr);
 	EXPECT_NE(second, nullptr);
-	EXPECT_NE(first, second);
+	// On-demand images are cached per time, so both fetches return the
+	// same image and the clip now reports as connected.
+	EXPECT_EQ(first, second);
+	EXPECT_TRUE(clip.getConnected());
 
 	first->releaseReference();
 	second->releaseReference();