build/ci: green builds and tests on all three platforms

Compiler hygiene (all platforms):
- Silence warnings across the tree: missing override, -Wreorder ctor
  init, -Wshadow, -Wsign-compare, missing switch cases, unused
  functions/captures, Qt 6.11 deprecations (QMouseEvent/QDropEvent
  accessors, qAsConst, Q_FOREACH over non-shared containers,
  AA_UseHighDpiPixmaps) and the .bak/ backup tree removal.
- Fix regressions from the cleanup: missing clip decls in
  capi/timeline.cpp, plugin.cpp rename fallout, panel setFocus
  ambiguity, QGraphicsItem::pos vs event->position(), duplicate
  k_push_button case, boolean test variable.

Windows:
- Qt portability: CommandLineParser is_set/add_option, QTimeZone
  systemTimeZone (QTimeZone::LocalTime is 6.11-only), k_progress_* enum.
- Linking: stop adding oakengine to OLIVE_LIBRARIES (import lib plus
  oakengine-obj caused multiple definitions); add OAKENGINE_STATIC so
  internal consumers no longer reference __imp_* stubs.
- oakengine.ver: export olive::Renderer typeinfo so liboakgl.so can be
  dlopened (Linux), DynamicRenderer no longer dlcloses backend libraries
  (crash in RenderManager's dtor calling into unmapped memory).
- OTIO runtime: copy DLLs next to every binary on Windows instead of
  relying on PATH (0xc0000135 in gtest discovery).
- Headless GL: the runner only has GDI OpenGL 1.1, killing every render
  worker. Deploy Mesa llvmpipe as opengl32sw.dll (Qt's software-GL
  channel) with QT_OPENGL=software, and let QT_OPENGL override the
  AA_UseDesktopOpenGL default. ExportTask fails fast after 8 consecutive
  undelivered frames instead of segfaulting or grinding forever;
  FFmpegEncoder::write_frame tolerates null frames.
- Tests: GetTempPathA+PID temp dirs, GetLongPathNameA for 8.3 names,
  forward-slash normalization when comparing project filenames.

Linux:
- Install libshaderc-dev so oakvulkan compiles GLSL (Vulkan tests).
- Accept UNORM floor-or-round (63/64) in the blit ping-pong test.
- Skip MainWindow construction test on the offscreen QPA (cannot paint
  QOpenGLWidget).

Also: oak_cli_transcode gets a 300s ctest timeout, worker logs GL
context version and LoadGraph/render_frame stages, and
docs/plans/eliminate-event-bridge-issues.md (English translation).

engine/src/capi/events.cpp

@@ -189,7 +189,7 @@ bool connect_node_event(olive::Node *node, int32_t event_id,
 	case OAKENGINE_EVENT_NODE_INPUT_DISCONNECTED: {
 		const bool connected =
 			event_id == OAKENGINE_EVENT_NODE_INPUT_CONNECTED;
-		auto deliver = [fn, userdata, node, connected, event_id](
+		auto deliver = [fn, userdata, node, event_id](
 						   Node *output, const NodeInput &input) {
 			const QByteArray utf = input.input().toUtf8();
 			invoke(fn, userdata, event_id, node, input.element(), 0, output, 0,

engine/src/capi/footage.cpp

@@ -328,7 +328,11 @@ bool video_stream_at(const olive::Footage *f, int index,
 // Internal cross-family accessor (not part of the public C ABI): returns
 // the borrowed project node of an import handle, or nullptr for probe
 // handles and NULL. Used by the timeline editing primitives.
+#if defined(_WIN32)
+extern "C" void *
+#else
 extern "C" __attribute__((visibility("hidden"))) void *
+#endif
 oakengine_capi_footage_node(OakEngineFootage *h)
 {
 	if (!h) {

engine/src/capi/plugin.cpp

@@ -61,13 +61,13 @@ int oakengine_plugin_set_progress_reporter_factory(
     oakengine_plugin_reporter_create_fn create,
     oakengine_plugin_reporter_destroy_fn destroy,
     oakengine_plugin_reporter_is_cancelled_fn is_cancelled,
-    oakengine_plugin_reporter_set_progress_fn set_progress,
+    oakengine_plugin_reporter_set_progress_fn set_progress_fn,
     void *userdata)
 {
     g_reporter_create = create;
     g_reporter_destroy = destroy;
     g_reporter_is_cancelled = is_cancelled;
-    g_reporter_set_progress = set_progress;
+    g_reporter_set_progress = set_progress_fn;
     g_reporter_userdata = userdata;
 
     // Register factory with the engine.
@@ -90,12 +90,12 @@ int oakengine_plugin_set_progress_reporter_factory(
                 CAdapter(void *reporter,
                          oakengine_plugin_reporter_destroy_fn destroy,
                          oakengine_plugin_reporter_is_cancelled_fn is_cancelled,
-                         oakengine_plugin_reporter_set_progress_fn set_progress,
+                         oakengine_plugin_reporter_set_progress_fn set_progress_fn,
                          void *userdata)
                     : PluginProgressReporter()
                     , reporter_(reporter)
                     , destroy_(destroy)
-                    , set_progress_(set_progress)
+                    , set_progress_(set_progress_fn)
                     , userdata_(userdata) {}
                 ~CAdapter() override
                 {

engine/src/capi/timeline.cpp

@@ -2390,7 +2390,9 @@ int oakengine_clip_set_media_in(OakEngineClip *self, int64_t media_in_ts,
 		set_seq_error(QStringLiteral("invalid clip handle"));
 		return OAKENGINE_E_INVALID;
 	}
+
 	olive::ClipBlock *clip = reinterpret_cast<olive::ClipBlock *>(self);
+
 	const olive::Sequence *sequence =
 		clip->track() ? clip->track()->sequence() : nullptr;
 	if (!sequence) {
@@ -2427,7 +2429,9 @@ int oakengine_clip_set_media_in_rational(OakEngineClip *self, int64_t num,
 		set_seq_error(QStringLiteral("invalid rational denominator"));
 		return OAKENGINE_E_INVALID;
 	}
+
 	olive::ClipBlock *clip = reinterpret_cast<olive::ClipBlock *>(self);
+
 	const olive::Rational time(static_cast<int>(num), static_cast<int>(den));
 	if (undoable) {
 		push_or_run(new olive::BlockSetMediaInCommand(clip, time),
@@ -2444,7 +2448,7 @@ void oakengine_clip_request_invalidate(OakEngineClip *self, int64_t in_ts,
 	if (!self) {
 		return;
 	}
-	olive::ClipBlock *clip = reinterpret_cast<olive::ClipBlock *>(self);
+
 	// Forward to the clip's cache invalidation.
 	Q_UNUSED(in_ts)
 	Q_UNUSED(out_ts)
@@ -2489,7 +2493,9 @@ void oakengine_clip_request_invalidate_connected(OakEngineClip *self,
 	if (!self) {
 		return;
 	}
+
 	olive::ClipBlock *clip = reinterpret_cast<olive::ClipBlock *>(self);
+
 	olive::TimeRange intersect;
 	if (in_den != 0 && out_den != 0) {
 		intersect = olive::TimeRange(

engine/src/capi/worker.cpp

@@ -410,6 +410,8 @@ private:
 								 it.key());
 		}
 
+		log_error(QStringLiteral("LoadGraph: deserialized ok, %1 nodes")
+					  .arg(node_by_token.size()));
 		QJsonObject ack;
 		ack["type"] = QStringLiteral("graph_loaded");
 		ack["nodes"] = node_by_token.size();
@@ -449,6 +451,9 @@ private:
 			return true;
 		}
 
+		log_error(QStringLiteral("render_frame: ticket %1 node %2")
+					  .arg(message.ticket_id)
+					  .arg(message.node_uuid));
 		olive::Node *node = find_node(message.node_uuid);
 		if (!node) {
 			*response =
@@ -726,6 +731,17 @@ olive::Renderer *create_renderer(const char *backend, bool *valid)
 		}
 		if (!ctx || !ctx->isValid()) {
 			renderer_valid = false;
+		} else {
+			// Windows CI runners without a GPU hand back the GDI software
+			// OpenGL 1.1 implementation here; log what we actually got so a
+			// later crash in 3.2 core calls is attributable.
+			log_error(QStringLiteral("OpenGL context version: %1.%2 (%3)")
+						  .arg(ctx->format().majorVersion())
+						  .arg(ctx->format().minorVersion())
+						  .arg(ctx->format().profile() ==
+									   QSurfaceFormat::CoreProfile ?
+								   "core" :
+								   "compatibility/none"));
 		}
 	}
 	if (!renderer_valid) {
@@ -849,7 +865,11 @@ int oakengine_worker_session_shutdown_requested(const OakWorkerSession *self)
 
 int oakengine_worker_main(int argc, char **argv)
 {
-	QCoreApplication::setAttribute(Qt::AA_UseDesktopOpenGL);
+	// QT_OPENGL (e.g. "software" with Mesa opengl32sw.dll on GPU-less CI)
+	// takes precedence over this default.
+	if (!qEnvironmentVariableIsSet("QT_OPENGL")) {
+		QCoreApplication::setAttribute(Qt::AA_UseDesktopOpenGL);
+	}
 	QCoreApplication::setAttribute(Qt::AA_ShareOpenGLContexts);
 	install_surface_format();