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

2 files changed, 80 insertions, 0 deletions

diff --git a/rust/crates/commands/src/project/mod.rs b/rust/crates/commands/src/project/mod.rs
new file mode 100644
index 00000000..28e9c92c
--- /dev/null
+++ b/rust/crates/commands/src/project/mod.rs
@@ -0,0 +1,3 @@
+pub mod update_project_settings;
+
+pub use update_project_settings::{ProjectSettingsPatch, UpdateProjectSettingsCommand};
diff --git a/rust/crates/commands/src/project/update_project_settings.rs b/rust/crates/commands/src/project/update_project_settings.rs
new file mode 100644
index 00000000..a0f6e99c
--- /dev/null
+++ b/rust/crates/commands/src/project/update_project_settings.rs
@@ -0,0 +1,77 @@
+use scene::{Background, CanvasSize, CanvasSizeMode, Project, ProjectSettings};
+use time::FrameRate;
+
+use crate::command::{Command, CommandError, CommandResult};
+
+#[derive(Clone, Debug, Default, PartialEq)]
+pub struct ProjectSettingsPatch {
+    pub fps: Option<FrameRate>,
+    pub canvas_size: Option<CanvasSize>,
+    pub canvas_size_mode: Option<Option<CanvasSizeMode>>,
+    pub last_custom_canvas_size: Option<Option<CanvasSize>>,
+    pub original_canvas_size: Option<Option<CanvasSize>>,
+    pub background: Option<Background>,
+}
+
+impl ProjectSettingsPatch {
+    pub fn apply_to(&self, settings: &mut ProjectSettings) {
+        if let Some(fps) = self.fps {
+            settings.fps = fps;
+        }
+        if let Some(canvas_size) = self.canvas_size {
+            settings.canvas_size = canvas_size;
+        }
+        if let Some(canvas_size_mode) = &self.canvas_size_mode {
+            settings.canvas_size_mode = *canvas_size_mode;
+        }
+        if let Some(last_custom_canvas_size) = &self.last_custom_canvas_size {
+            settings.last_custom_canvas_size = *last_custom_canvas_size;
+        }
+        if let Some(original_canvas_size) = &self.original_canvas_size {
+            settings.original_canvas_size = *original_canvas_size;
+        }
+        if let Some(background) = &self.background {
+            settings.background = background.clone();
+        }
+    }
+}
+
+pub struct UpdateProjectSettingsCommand {
+    updates: ProjectSettingsPatch,
+    saved_settings: Option<ProjectSettings>,
+    saved_updated_at: Option<chrono::DateTime<chrono::Utc>>,
+}
+
+impl UpdateProjectSettingsCommand {
+    pub fn new(updates: ProjectSettingsPatch) -> Self {
+        Self {
+            updates,
+            saved_settings: None,
+            saved_updated_at: None,
+        }
+    }
+}
+
+impl Command for UpdateProjectSettingsCommand {
+    fn execute(
+        &mut self,
+        project: &mut Project,
+    ) -> Result<Option<CommandResult>, CommandError> {
+        self.saved_settings = Some(project.settings.clone());
+        self.saved_updated_at = Some(project.metadata.updated_at);
+
+        self.updates.apply_to(&mut project.settings);
+        project.metadata.updated_at = chrono::Utc::now();
+        Ok(None)
+    }
+
+    fn undo(&mut self, project: &mut Project) {
+        let (Some(saved_settings), Some(saved_updated_at)) =
+            (&self.saved_settings, self.saved_updated_at)
+        else {
+            return;
+        };
+        project.settings = saved_settings.clone();
+        project.metadata.updated_at = saved_updated_at;
+    }
+}