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, 61 insertions, 0 deletions

diff --git a/rust/crates/commands/src/batch_command.rs b/rust/crates/commands/src/batch_command.rs
new file mode 100644
index 00000000..bd928d33
--- /dev/null
+++ b/rust/crates/commands/src/batch_command.rs
@@ -0,0 +1,61 @@
+use scene::Project;
+
+use crate::command::{Command, CommandError, CommandResult};
+
+pub struct BatchCommand {
+    commands: Vec<Box<dyn Command>>,
+}
+
+impl BatchCommand {
+    pub fn new(commands: Vec<Box<dyn Command>>) -> Self {
+        Self { commands }
+    }
+
+    pub fn len(&self) -> usize {
+        self.commands.len()
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.commands.is_empty()
+    }
+}
+
+impl Command for BatchCommand {
+    fn execute(
+        &mut self,
+        project: &mut Project,
+    ) -> Result<Option<CommandResult>, CommandError> {
+        let mut latest_selection_result = None;
+
+        for command in &mut self.commands {
+            let result = command.execute(project)?;
+            if result.as_ref().and_then(|r| r.selection.as_ref()).is_some() {
+                latest_selection_result = result;
+            }
+        }
+
+        Ok(latest_selection_result)
+    }
+
+    fn undo(&mut self, project: &mut Project) {
+        for command in self.commands.iter_mut().rev() {
+            command.undo(project);
+        }
+    }
+
+    fn redo(
+        &mut self,
+        project: &mut Project,
+    ) -> Result<Option<CommandResult>, CommandError> {
+        let mut latest_selection_result = None;
+
+        for command in &mut self.commands {
+            let result = command.redo(project)?;
+            if result.as_ref().and_then(|r| r.selection.as_ref()).is_some() {
+                latest_selection_result = result;
+            }
+        }
+
+        Ok(latest_selection_result)
+    }
+}