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

app/node/node.cpp

@@ -497,8 +497,19 @@ QVariant Node::GetSplitValueAtTimeOnTrack(const QString &input,
 
 				double before_val, after_val, interpolated;
 				if (type == NodeValue::kRational) {
-					before_val = before->value().value<rational>().toDouble();
-					after_val = after->value().value<rational>().toDouble();
+					// Keys for rational inputs usually hold rationals, but may
+					// hold plain doubles, in which case we convert to rational
+					// first to preserve the value
+					before_val = (before->value().canConvert<rational>() ?
+									  before->value().value<rational>() :
+									  rational::fromDouble(
+										  before->value().toDouble()))
+									 .toDouble();
+					after_val = (after->value().canConvert<rational>() ?
+									 after->value().value<rational>() :
+									 rational::fromDouble(
+										 after->value().toDouble()))
+									.toDouble();
 				} else {
 					before_val = before->value().toDouble();
 					after_val = after->value().toDouble();
@@ -1724,7 +1735,10 @@ bool Node::LoadImmediate(QXmlStreamReader *reader, const QString &input,
 							key->set_element(element);
 							key->set_track(track);
 
-							key->load(reader, data_type);
+							if (!key->load(reader, data_type)) {
+								delete key;
+								return false;
+							}
 							key->setParent(this);
 						} else {
 							reader->skipCurrentElement();