feat(engine): clip move, clip effect_input, mandatory static FFmpeg

- oakengine_sequence_move_clip implemented for real (oaktimeline
  TrackMoveBlockCommand; fixes the graph-ownership/gap-anchor/ripple
  trim bugs the stub was hiding); same-track via the frozen C ABI,
  cross-track supported by the module command
- oaknode clip blocks now declare a tex_in texture input and set
  effect_input to it, so timeline clips can host effect chains; facade
  test covers effect insert/remove on a real clip
- oakffmpeg-link: FFMPEG_DIR is now mandatory with a clear panic (a
  Homebrew upgrade left the system ffmpeg .pc pointing at a deleted
  dav1d Cellar path, breaking links); reads a git-ignored workspace
  .env for IDEs that cannot inject env vars (RustRover); links the C++
  stdlib for C++ codec libs (svt-av1)
- oakengine re-exports oaknode so tests share one crate instance;
  it_node uses the direct instance's value type where it calls the
  module FFI (the --workspace dev-dependency feature split builds
  oaknode twice)

crates/oaknode/src/nodes/solid.rs

@@ -120,7 +120,10 @@ pub fn create() -> (NodeCore, Box<dyn NodeBehavior>) {
 		crate::value::ValueType::Color,
 		crate::value::NodeValue::Color([1.0, 0.0, 0.0, 1.0]),
 	);
-	color.properties = vec![("view".to_string(), crate::value::NodeValue::Text("color".into()))];
+	color.properties = vec![(
+		"view".to_string(),
+		crate::value::NodeValue::Text("color".into()),
+	)];
 	core.add_input(color);
 	(core, Box::new(SolidGenerator))
 }
@@ -142,7 +145,10 @@ mod tests {
 	#[test]
 	fn create_wires_inputs() {
 		let (core, behavior) = create();
-		assert_eq!(behavior.type_id(), "org.olivevideoeditor.Olive.solidgenerator");
+		assert_eq!(
+			behavior.type_id(),
+			"org.olivevideoeditor.Olive.solidgenerator"
+		);
 		assert_eq!(
 			core.get_input(COLOR_INPUT).unwrap().default,
 			NodeValue::Color([1.0, 0.0, 0.0, 1.0])