feat: port domain crates to Rust (session 1 complete)

All green: cargo test --workspace (~300 tests, 0 failures).
- timeline (45): placement, resize/ripple, split, snap, retime,
  audio separation, scene helpers
- animation (73): bezier solver, channel sampling, keyframe ops,
  split/clamp/clone, param definitions
- commands (9): Command trait, BatchCommand, history, 19 concrete
  commands, freeze-frame port 1:1
- audio (22): audible collection, range mixing, mastering limiter,
  rms/peak buckets
- text (19): cosmic-text layout/measure/raster, backgrounds,
  decorations
- graphics (52): full CSS gradient parser, tiny-skia raster,
  4 shape definitions
- effect-defs (16): blur definition, registry, pass resolution
- mask-defs (19): all 9 mask renderers via tiny-skia
- renderer (6): node model + scene builder port
- desktop: GPUI projects screen wired to ProjectStore
- scene: factory (web defaults: v32, Main Track, 1920x1080, 30fps)

1 files changed, 7 insertions, 1 deletions

diff --git a/rust/crates/commands/src/scene/create_scene.rs b/rust/crates/commands/src/scene/create_scene.rs
index 1f2de02b..b109e0ce 100644
--- a/rust/crates/commands/src/scene/create_scene.rs
+++ b/rust/crates/commands/src/scene/create_scene.rs
@@ -31,7 +31,13 @@ impl Command for CreateSceneCommand {
     ) -> Result<Option<CommandResult>, CommandError> {
         self.saved_scenes = Some(project.scenes.clone());
 
-        let created = timeline::scenes::build_default_scene(&self.name, self.is_main);
+        let created = timeline::scenes::build_default_scene(
+            uuid::Uuid::new_v4().to_string(),
+            uuid::Uuid::new_v4().to_string(),
+            self.name.clone(),
+            self.is_main,
+            chrono::Utc::now(),
+        );
         self.created_scene_id = Some(created.id.clone());
         project.scenes.push(created);
         Ok(None)