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/tests/oakengine_disk_test.cpp

@@ -32,6 +32,7 @@
 #if defined(_WIN32)
 #include <direct.h>
 #include <io.h>
+#include <windows.h>
 #else
 #include <sys/stat.h>
 #include <unistd.h>
@@ -113,20 +114,18 @@ static void test_open_folder_handle(void)
 	EXPECT_TRUE(empty_folder == folder);
 
 	// A different path opens a distinct folder.
-	char tmp[256];
-	snprintf(tmp, sizeof(tmp),
+	char tmp[512];
 #if defined(_WIN32)
-			 "%s\\oakengine_disk_test_folder_XXXXXX",
-#else
-			 "%s/oakengine_disk_test_folder_XXXXXX",
-#endif
-			 getenv("TMPDIR") ? getenv("TMPDIR") : "/tmp");
-
-#if defined(_WIN32)
-	char *tmpdir = _mktemp(tmp);
-	EXPECT_TRUE(tmpdir != NULL);
+	char base[MAX_PATH];
+	const DWORD len = GetTempPathA(MAX_PATH, base);
+	EXPECT_TRUE(len > 0 && len < MAX_PATH);
+	snprintf(tmp, sizeof(tmp), "%soakengine_disk_test_folder_%lu", base,
+			 (unsigned long)GetCurrentProcessId());
+	char *tmpdir = tmp;
 	EXPECT_TRUE(_mkdir(tmpdir) == 0);
 #else
+	snprintf(tmp, sizeof(tmp), "%s/oakengine_disk_test_folder_XXXXXX",
+			 getenv("TMPDIR") ? getenv("TMPDIR") : "/tmp");
 	char *tmpdir = mkdtemp(tmp);
 	EXPECT_TRUE(tmpdir != NULL);
 #endif
@@ -149,20 +148,18 @@ static void test_open_folder_handle(void)
 static void test_clear_cache(void)
 {
 	// Create a temporary cache directory and seed it with a file.
-	char path[256];
-	snprintf(path, sizeof(path),
+	char path[512];
 #if defined(_WIN32)
-			 "%s\\oakengine_disk_test_cache_XXXXXX",
-#else
-			 "%s/oakengine_disk_test_cache_XXXXXX",
-#endif
-			 getenv("TMPDIR") ? getenv("TMPDIR") : "/tmp");
-
-#if defined(_WIN32)
-	char *tmpdir = _mktemp(path);
-	EXPECT_TRUE(tmpdir != NULL);
+	char base[MAX_PATH];
+	const DWORD len = GetTempPathA(MAX_PATH, base);
+	EXPECT_TRUE(len > 0 && len < MAX_PATH);
+	snprintf(path, sizeof(path), "%soakengine_disk_test_cache_%lu", base,
+			 (unsigned long)GetCurrentProcessId());
+	char *tmpdir = path;
 	EXPECT_TRUE(_mkdir(tmpdir) == 0);
 #else
+	snprintf(path, sizeof(path), "%s/oakengine_disk_test_cache_XXXXXX",
+			 getenv("TMPDIR") ? getenv("TMPDIR") : "/tmp");
 	char *tmpdir = mkdtemp(path);
 	EXPECT_TRUE(tmpdir != NULL);
 #endif
@@ -244,20 +241,18 @@ static void test_set_default_cache_path(void)
 	EXPECT_TRUE(oakengine_disk_get_default_cache_path(original, sizeof(original)) >
 		   0);
 
-	char tmp[256];
-	snprintf(tmp, sizeof(tmp),
+	char tmp[512];
 #if defined(_WIN32)
-			 "%s\\oakengine_disk_test_default_XXXXXX",
-#else
-			 "%s/oakengine_disk_test_default_XXXXXX",
-#endif
-			 getenv("TMPDIR") ? getenv("TMPDIR") : "/tmp");
-
-#if defined(_WIN32)
-	char *tmpdir = _mktemp(tmp);
-	EXPECT_TRUE(tmpdir != NULL);
+	char base[MAX_PATH];
+	const DWORD len = GetTempPathA(MAX_PATH, base);
+	EXPECT_TRUE(len > 0 && len < MAX_PATH);
+	snprintf(tmp, sizeof(tmp), "%soakengine_disk_test_default_%lu", base,
+			 (unsigned long)GetCurrentProcessId());
+	char *tmpdir = tmp;
 	EXPECT_TRUE(_mkdir(tmpdir) == 0);
 #else
+	snprintf(tmp, sizeof(tmp), "%s/oakengine_disk_test_default_XXXXXX",
+			 getenv("TMPDIR") ? getenv("TMPDIR") : "/tmp");
 	char *tmpdir = mkdtemp(tmp);
 	EXPECT_TRUE(tmpdir != NULL);
 #endif