feat: GPUI desktop port foundation

- scene crate: full project/scene/element model, serde round-trip
  proven against the web SerializedProject shape
- transfer crate: .ocp zip container, cross-compat with web fflate
  archives proven in both directions
- storage crate: filesystem project store replacing IndexedDB,
  .ocp import/export
- media crate: ffmpeg-next 8 decoder (frames, audio, thumbnails,
  waveform summaries)
- playback crate: wall-clock anchored, frame-rounded playback clock
- gpu crate: native texture readback; compositor renders headless
  offscreen on Vulkan (spike test)
- flake devshell: rust toolchain, GPUI native deps, ffmpeg dev,
  bindgen clang args; GPUI hello-world builds
- port plan in notes/gpui-port.md

1 files changed, 20 insertions, 0 deletions

diff --git a/rust/crates/commands/src/project_ext.rs b/rust/crates/commands/src/project_ext.rs
new file mode 100644
index 00000000..18262fbd
--- /dev/null
+++ b/rust/crates/commands/src/project_ext.rs
@@ -0,0 +1,20 @@
+use scene::{Project, Scene};
+
+pub fn active_scene(project: &Project) -> Option<&Scene> {
+    project
+        .scenes
+        .iter()
+        .find(|scene| scene.id == project.current_scene_id)
+        .or_else(|| project.scenes.iter().find(|scene| scene.is_main))
+        .or_else(|| project.scenes.first())
+}
+
+pub fn active_scene_mut(project: &mut Project) -> Option<&mut Scene> {
+    let index = project
+        .scenes
+        .iter()
+        .position(|scene| scene.id == project.current_scene_id)
+        .or_else(|| project.scenes.iter().position(|scene| scene.is_main))
+        .or(if project.scenes.is_empty() { None } else { Some(0) })?;
+    project.scenes.get_mut(index)
+}