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/render/ipc/sharedmemoryregion.cpp

@@ -166,6 +166,26 @@ bool SharedMemoryRegion::Open(const QString &key, size_t size, Mode mode)
 			shm_unlink(name_bytes.constData());
 			return false;
 		}
+	} else {
+		// mmap() succeeds even beyond the real segment size and only faults
+		// (SIGBUS) on access, so verify the segment is large enough up front.
+		struct stat st;
+		if (fstat(fd_, &st) != 0) {
+			error_ = QStringLiteral("fstat failed: %1")
+						 .arg(QString::fromUtf8(strerror(errno)));
+			::close(fd_);
+			fd_ = -1;
+			return false;
+		}
+		if (st.st_size < off_t(size)) {
+			error_ = QStringLiteral(
+						 "shared memory segment is %1 bytes, smaller than the requested %2")
+						 .arg(qint64(st.st_size))
+						 .arg(qint64(size));
+			::close(fd_);
+			fd_ = -1;
+			return false;
+		}
 	}
 
 	data_ = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd_, 0);