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, 19 insertions, 0 deletions

diff --git a/rust/crates/scene/src/iso_date.rs b/rust/crates/scene/src/iso_date.rs
new file mode 100644
index 00000000..82fb7828
--- /dev/null
+++ b/rust/crates/scene/src/iso_date.rs
@@ -0,0 +1,19 @@
+use serde::{Deserialize, Deserializer, Serializer};
+use chrono::{DateTime, SecondsFormat, Utc};
+
+pub fn serialize<S>(date: &DateTime<Utc>, serializer: S) -> Result<S::Ok, S::Error>
+where
+    S: Serializer,
+{
+    serializer.serialize_str(&date.to_rfc3339_opts(SecondsFormat::Millis, true))
+}
+
+pub fn deserialize<'de, D>(deserializer: D) -> Result<DateTime<Utc>, D::Error>
+where
+    D: Deserializer<'de>,
+{
+    let s = String::deserialize(deserializer)?;
+    DateTime::parse_from_rfc3339(&s)
+        .map(|d| d.with_timezone(&Utc))
+        .map_err(serde::de::Error::custom)
+}