refactor: drop internal bridge/ffi layers; exporter family lands

Single-lib cleanup: the per-crate src/bridge/ and src/ffi.rs layers are
gone (oakundo/oakcommon/oaknode/oaktimeline/oakcodec/oakaudio/
oakrender/oaktask/oakplugin/oakstorage); cross-crate calls are plain
Rust, CHandle marshalling shrinks to the oakengine boundary, and tests
call the Rust APIs directly (pure C-ABI wrapper tests removed where
the domain layer already covers the behavior).

exporter.h family implemented: oakengine_export_render (CLI contract),
oakengine_export_render_with_params (was a stub), last_error and
progress callback; synchronous path reuses task_create_export +
start_sync. Fixes on the way: oaktask video ticket self-deadlock,
audio params dropped on the export path, codec encoder AAC slicing and
H.264 time base. Real-mp4 tests cover both entry points, progress and
the illegal-argument matrix.

Also: oakstorage session maps null project handles to None (version-
info path), configstore test double literal 3.14 -> 3.15 (clippy PI
lint), oakaudio output callback scratch buffer + env-aware P1 test,
cli media round-trip test uses a generated 16-frame clip (no more
minute-long debug runs).

crates/oakcommon/src/configstore.rs

@@ -729,7 +729,7 @@ mod tests {
 		assert_eq!(format_g(-0.0), "-0");
 		assert_eq!(format_g(1920.0), "1920");
 		assert_eq!(format_g(100.0), "100");
-		assert_eq!(format_g(3.14), "3.14");
+		assert_eq!(format_g(3.15), "3.15");
 		assert_eq!(format_g(1.5), "1.5");
 		assert_eq!(format_g(0.1), "0.1");
 		assert_eq!(format_g(-3.5), "-3.5");
@@ -848,9 +848,9 @@ mod tests {
 		let _g = test_lock().lock().unwrap();
 		let s = ConfigStore::instance();
 		s.reset_defaults().unwrap();
-		s.set_double(None, "MyD", 3.14);
-		assert_eq!(s.get_double(None, "MyD", -1.0), 3.14);
-		assert_eq!(s.get(None, "MyD").unwrap(), "3.14");
+		s.set_double(None, "MyD", 3.15);
+		assert_eq!(s.get_double(None, "MyD", -1.0), 3.15);
+		assert_eq!(s.get(None, "MyD").unwrap(), "3.15");
 		assert_eq!(s.entry_type(None, "MyD").unwrap(), EntryType::Double);
 
 		assert_eq!(s.get_double(None, "MissingD", 2.5), 2.5);

crates/oakcommon/src/lib.rs

@@ -27,7 +27,6 @@ pub mod commandlineparser;
 pub mod configstore;
 pub mod debug;
 pub mod error;
-pub mod ffi;
 pub mod ffmpegutils;
 pub mod filefunctions;
 pub mod handle;

crates/oakcommon/src/subtitleparams.rs

@@ -41,6 +41,7 @@ pub struct Subtitle {
 }
 
 /// `olive::SubtitleParams` — a handle-wrapped subtitle parameter set.
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub struct SubtitleParams {
 	/// Stream index within the source file.
 	stream_index: i32,

crates/oakcommon/src/videoparams.rs

@@ -56,7 +56,7 @@ pub enum ColorRange {
 }
 
 /// `olive::VideoParams` — a handle-wrapped video parameter set.
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct VideoParams {
 	/// Frame width in pixels.
 	width: i32,