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/ipcmessage.cpp

@@ -38,37 +38,36 @@ bool WriteMessage(QIODevice *device, const QJsonObject &obj)
 
 bool ReadMessage(QByteArray *buffer, QJsonObject *out, bool *ok)
 {
-	const int newline = buffer->indexOf('\n');
-	if (newline < 0) {
-		// No complete line buffered yet.
-		return false;
-	}
-
-	const QByteArray line = buffer->left(newline);
-	buffer->remove(0, newline + 1);
-
-	// Skip blank lines silently (e.g. a stray newline) without flagging an error.
-	if (line.trimmed().isEmpty()) {
-		if (ok) {
-			*ok = false;
+	while (true) {
+		const int newline = buffer->indexOf('\n');
+		if (newline < 0) {
+			// No complete line buffered yet.
+			return false;
 		}
-		return false;
-	}
 
-	QJsonParseError err;
-	const QJsonDocument doc = QJsonDocument::fromJson(line, &err);
-	if (err.error != QJsonParseError::NoError || !doc.isObject()) {
-		if (ok) {
-			*ok = false;
+		const QByteArray line = buffer->left(newline);
+		buffer->remove(0, newline + 1);
+
+		// Skip blank lines silently (e.g. a stray newline) without flagging an error.
+		if (line.trimmed().isEmpty()) {
+			continue;
 		}
-		return false;
-	}
 
-	*out = doc.object();
-	if (ok) {
-		*ok = true;
+		QJsonParseError err;
+		const QJsonDocument doc = QJsonDocument::fromJson(line, &err);
+		if (err.error != QJsonParseError::NoError || !doc.isObject()) {
+			if (ok) {
+				*ok = false;
+			}
+			return false;
+		}
+
+		*out = doc.object();
+		if (ok) {
+			*ok = true;
+		}
+		return true;
 	}
-	return true;
 }
 
 // ---- HandshakeMsg ---------------------------------------------------------------------------

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);