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, 49 insertions, 0 deletions

diff --git a/rust/crates/commands/src/scene/update_bookmark.rs b/rust/crates/commands/src/scene/update_bookmark.rs
new file mode 100644
index 00000000..f2c9b94e
--- /dev/null
+++ b/rust/crates/commands/src/scene/update_bookmark.rs
@@ -0,0 +1,49 @@
+use scene::Project;
+use time::MediaTime;
+
+use crate::bookmarks::{BookmarkPatch, get_frame_time, update_bookmark_in_array};
+use crate::command::{Command, CommandError, CommandResult};
+use crate::project_ext::active_scene_mut;
+
+pub struct UpdateBookmarkCommand {
+    time: MediaTime,
+    updates: BookmarkPatch,
+    saved_bookmarks: Option<Vec<scene::Bookmark>>,
+}
+
+impl UpdateBookmarkCommand {
+    pub fn new(time: MediaTime, updates: BookmarkPatch) -> Self {
+        Self {
+            time,
+            updates,
+            saved_bookmarks: None,
+        }
+    }
+}
+
+impl Command for UpdateBookmarkCommand {
+    fn execute(
+        &mut self,
+        project: &mut Project,
+    ) -> Result<Option<CommandResult>, CommandError> {
+        let fps = project.settings.fps;
+        let Some(scene) = active_scene_mut(project) else {
+            return Ok(None);
+        };
+
+        self.saved_bookmarks = Some(scene.bookmarks.clone());
+        let frame_time = get_frame_time(self.time, fps);
+        scene.bookmarks =
+            update_bookmark_in_array(&scene.bookmarks, frame_time, &self.updates);
+        Ok(None)
+    }
+
+    fn undo(&mut self, project: &mut Project) {
+        let Some(saved) = &self.saved_bookmarks else {
+            return;
+        };
+        if let Some(scene) = active_scene_mut(project) {
+            scene.bookmarks = saved.clone();
+        }
+    }
+}