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, 127 insertions, 0 deletions

diff --git a/rust/crates/scene/src/animation.rs b/rust/crates/scene/src/animation.rs
new file mode 100644
index 00000000..d09dd3de
--- /dev/null
+++ b/rust/crates/scene/src/animation.rs
@@ -0,0 +1,127 @@
+use serde::{Deserialize, Serialize};
+use std::collections::BTreeMap;
+use time::MediaTime;
+
+use crate::params::ParamValue;
+
+pub const ANIMATION_PROPERTY_PATHS: &[&str] = &[
+    "transform.positionX",
+    "transform.positionY",
+    "transform.scaleX",
+    "transform.scaleY",
+    "transform.rotate",
+    "opacity",
+    "volume",
+    "color",
+    "background.color",
+    "background.paddingX",
+    "background.paddingY",
+    "background.offsetX",
+    "background.offsetY",
+    "background.cornerRadius",
+];
+
+#[derive(Serialize, Deserialize, Clone, Copy, Debug, Eq, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub enum ScalarSegmentType {
+    Step,
+    Linear,
+    Bezier,
+}
+
+#[derive(Serialize, Deserialize, Clone, Copy, Debug, Eq, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub enum TangentMode {
+    Auto,
+    Aligned,
+    Broken,
+    Flat,
+}
+
+#[derive(Serialize, Deserialize, Clone, Copy, Debug, Eq, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub enum ChannelExtrapolationMode {
+    Hold,
+    Linear,
+}
+
+#[derive(Serialize, Deserialize, Clone, Copy, Debug, PartialEq)]
+pub struct CurveHandle {
+    pub dt: MediaTime,
+    pub dv: f64,
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct ScalarAnimationKey {
+    pub id: String,
+    pub time: MediaTime,
+    pub value: f64,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub left_handle: Option<CurveHandle>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub right_handle: Option<CurveHandle>,
+    pub segment_to_next: ScalarSegmentType,
+    pub tangent_mode: TangentMode,
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
+#[serde(untagged)]
+pub enum DiscreteValue {
+    Bool(bool),
+    String(String),
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct DiscreteAnimationKey {
+    pub id: String,
+    pub time: MediaTime,
+    pub value: DiscreteValue,
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct ChannelExtrapolation {
+    pub before: ChannelExtrapolationMode,
+    pub after: ChannelExtrapolationMode,
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
+pub struct ScalarChannel {
+    pub keys: Vec<ScalarAnimationKey>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub extrapolation: Option<ChannelExtrapolation>,
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
+pub struct DiscreteChannel {
+    pub keys: Vec<DiscreteAnimationKey>,
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
+#[serde(untagged)]
+pub enum AnimationChannel {
+    Scalar(ScalarChannel),
+    Discrete(DiscreteChannel),
+}
+
+pub type CompositeChannelData = BTreeMap<String, AnimationChannel>;
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
+#[serde(untagged)]
+pub enum ChannelData {
+    Single(AnimationChannel),
+    Composite(CompositeChannelData),
+}
+
+pub type ElementAnimations = BTreeMap<String, ChannelData>;
+
+impl From<DiscreteValue> for ParamValue {
+    fn from(value: DiscreteValue) -> Self {
+        match value {
+            DiscreteValue::Bool(b) => ParamValue::Bool(b),
+            DiscreteValue::String(s) => ParamValue::String(s),
+        }
+    }
+}