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, 128 insertions, 0 deletions

diff --git a/rust/crates/scene/src/mask.rs b/rust/crates/scene/src/mask.rs
new file mode 100644
index 00000000..12f026d2
--- /dev/null
+++ b/rust/crates/scene/src/mask.rs
@@ -0,0 +1,128 @@
+use serde::{Deserialize, Serialize};
+
+#[derive(Serialize, Deserialize, Clone, Copy, Debug, Eq, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub enum StrokeAlign {
+    Inside,
+    Center,
+    Outside,
+}
+
+#[derive(Serialize, Deserialize, Clone, Copy, Debug, Eq, PartialEq)]
+pub enum TextFontWeight {
+    #[serde(rename = "normal")]
+    Normal,
+    #[serde(rename = "bold")]
+    Bold,
+}
+
+#[derive(Serialize, Deserialize, Clone, Copy, Debug, Eq, PartialEq)]
+pub enum TextFontStyle {
+    #[serde(rename = "normal")]
+    Normal,
+    #[serde(rename = "italic")]
+    Italic,
+}
+
+#[derive(Serialize, Deserialize, Clone, Copy, Debug, Eq, PartialEq)]
+pub enum TextDecoration {
+    #[serde(rename = "none")]
+    None,
+    #[serde(rename = "underline")]
+    Underline,
+    #[serde(rename = "line-through")]
+    LineThrough,
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct FreeformPathPoint {
+    pub id: String,
+    pub x: f64,
+    pub y: f64,
+    pub in_x: f64,
+    pub in_y: f64,
+    pub out_x: f64,
+    pub out_y: f64,
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct SplitMaskParams {
+    pub feather: f64,
+    pub inverted: bool,
+    pub stroke_color: String,
+    pub stroke_width: f64,
+    pub stroke_align: StrokeAlign,
+    pub center_x: f64,
+    pub center_y: f64,
+    pub rotation: f64,
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct RectangleMaskParams {
+    pub feather: f64,
+    pub inverted: bool,
+    pub stroke_color: String,
+    pub stroke_width: f64,
+    pub stroke_align: StrokeAlign,
+    pub center_x: f64,
+    pub center_y: f64,
+    pub width: f64,
+    pub height: f64,
+    pub rotation: f64,
+    pub scale: f64,
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct TextMaskParams {
+    pub feather: f64,
+    pub inverted: bool,
+    pub stroke_color: String,
+    pub stroke_width: f64,
+    pub stroke_align: StrokeAlign,
+    pub content: String,
+    pub font_size: f64,
+    pub font_family: String,
+    pub font_weight: TextFontWeight,
+    pub font_style: TextFontStyle,
+    pub text_decoration: TextDecoration,
+    pub letter_spacing: f64,
+    pub line_height: f64,
+    pub center_x: f64,
+    pub center_y: f64,
+    pub rotation: f64,
+    pub scale: f64,
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct FreeformPathMaskParams {
+    pub feather: f64,
+    pub inverted: bool,
+    pub stroke_color: String,
+    pub stroke_width: f64,
+    pub stroke_align: StrokeAlign,
+    pub path: Vec<FreeformPathPoint>,
+    pub closed: bool,
+    pub center_x: f64,
+    pub center_y: f64,
+    pub rotation: f64,
+    pub scale: f64,
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
+#[serde(tag = "type", rename_all = "kebab-case")]
+pub enum Mask {
+    Split { id: String, params: SplitMaskParams },
+    CinematicBars { id: String, params: RectangleMaskParams },
+    Rectangle { id: String, params: RectangleMaskParams },
+    Ellipse { id: String, params: RectangleMaskParams },
+    Heart { id: String, params: RectangleMaskParams },
+    Diamond { id: String, params: RectangleMaskParams },
+    Star { id: String, params: RectangleMaskParams },
+    Text { id: String, params: TextMaskParams },
+    Freeform { id: String, params: FreeformPathMaskParams },
+}