feat: port domain crates to Rust (session 1 complete)

All green: cargo test --workspace (~300 tests, 0 failures).
- timeline (45): placement, resize/ripple, split, snap, retime,
  audio separation, scene helpers
- animation (73): bezier solver, channel sampling, keyframe ops,
  split/clamp/clone, param definitions
- commands (9): Command trait, BatchCommand, history, 19 concrete
  commands, freeze-frame port 1:1
- audio (22): audible collection, range mixing, mastering limiter,
  rms/peak buckets
- text (19): cosmic-text layout/measure/raster, backgrounds,
  decorations
- graphics (52): full CSS gradient parser, tiny-skia raster,
  4 shape definitions
- effect-defs (16): blur definition, registry, pass resolution
- mask-defs (19): all 9 mask renderers via tiny-skia
- renderer (6): node model + scene builder port
- desktop: GPUI projects screen wired to ProjectStore
- scene: factory (web defaults: v32, Main Track, 1920x1080, 30fps)

1 files changed, 172 insertions, 0 deletions

diff --git a/rust/crates/text/tests/raster.rs b/rust/crates/text/tests/raster.rs
new file mode 100644
index 00000000..2e6921a5
--- /dev/null
+++ b/rust/crates/text/tests/raster.rs
@@ -0,0 +1,172 @@
+use text::{
+    Color, RasterOptions, StrokeStyle, TextAlign, TextBackground, TextEngine, TextLayoutParams,
+    rasterize, text_visual_rect,
+};
+
+const FONT_REGULAR: &[u8] = include_bytes!("fixtures/DejaVuSans.ttf");
+const FONT_BOLD: &[u8] = include_bytes!("fixtures/DejaVuSans-Bold.ttf");
+
+fn engine() -> TextEngine {
+    TextEngine::with_font_bytes(&[FONT_REGULAR, FONT_BOLD])
+}
+
+fn params(content: &str) -> TextLayoutParams {
+    TextLayoutParams {
+        content: content.to_string(),
+        font_family: "DejaVu Sans".to_string(),
+        ..TextLayoutParams::default()
+    }
+}
+
+fn opaque_pixels(buffer: &text::RgbaBuffer) -> usize {
+    buffer.pixels.chunks(4).filter(|px| px[3] > 0).count()
+}
+
+#[test]
+fn raster_produces_non_empty_output_with_visual_rect_dimensions() {
+    let mut engine = engine();
+    let measured = engine.measure(&params("Hello"), 90.0);
+    let visual = text_visual_rect(
+        TextAlign::Center,
+        &measured.block,
+        &TextBackground::default(),
+        1.0,
+    );
+    let buffer = rasterize(
+        &mut engine,
+        &measured,
+        &RasterOptions {
+            text_color: Color::rgb(255, 255, 255),
+            background: None,
+            stroke: None,
+        },
+    );
+
+    assert_eq!(buffer.width, visual.width.ceil() as u32);
+    assert_eq!(buffer.height, visual.height.ceil() as u32);
+    assert_eq!(buffer.pixels.len(), buffer.width as usize * buffer.height as usize * 4);
+    assert!(opaque_pixels(&buffer) > 0);
+    assert_eq!(buffer.pixel(0, 0).a, 0);
+}
+
+#[test]
+fn raster_fills_background_inside_padded_box() {
+    let mut engine = engine();
+    let measured = engine.measure(&params("Hello"), 90.0);
+    let background = TextBackground {
+        enabled: true,
+        color: "#ff0000".to_string(),
+        ..TextBackground::default()
+    };
+    let red = Color::rgb(255, 0, 0);
+    let buffer = rasterize(
+        &mut engine,
+        &measured,
+        &RasterOptions {
+            text_color: Color::rgb(255, 255, 255),
+            background: Some((&background, red)),
+            stroke: None,
+        },
+    );
+
+    assert_eq!(buffer.height, 102);
+    let corner = buffer.pixel(2, 2);
+    assert!(corner.a > 200);
+    assert!(corner.r > 200);
+    assert!(corner.g < 60);
+    assert!(corner.b < 60);
+}
+
+#[test]
+fn raster_dimensions_grow_with_background_padding() {
+    let mut engine = engine();
+    let measured = engine.measure(&params("Hello"), 90.0);
+    let plain = rasterize(
+        &mut engine,
+        &measured,
+        &RasterOptions {
+            text_color: Color::rgb(255, 255, 255),
+            background: None,
+            stroke: None,
+        },
+    );
+    let background = TextBackground {
+        enabled: true,
+        color: "#ff0000".to_string(),
+        ..TextBackground::default()
+    };
+    let padded = rasterize(
+        &mut engine,
+        &measured,
+        &RasterOptions {
+            text_color: Color::rgb(255, 255, 255),
+            background: Some((&background, Color::rgb(255, 0, 0))),
+            stroke: None,
+        },
+    );
+
+    assert_eq!(padded.width, plain.width + 60);
+    assert_eq!(padded.height, plain.height + 84);
+}
+
+#[test]
+fn raster_underline_adds_pixels_below_text() {
+    let mut engine = engine();
+    let plain_params = params("Hello");
+    let plain = engine.measure(&plain_params, 90.0);
+    let plain_buffer = rasterize(
+        &mut engine,
+        &plain,
+        &RasterOptions {
+            text_color: Color::rgb(255, 255, 255),
+            background: None,
+            stroke: None,
+        },
+    );
+
+    let underlined_params = TextLayoutParams {
+        text_decoration: text::TextDecoration::Underline,
+        ..params("Hello")
+    };
+    let underlined = engine.measure(&underlined_params, 90.0);
+    let underlined_buffer = rasterize(
+        &mut engine,
+        &underlined,
+        &RasterOptions {
+            text_color: Color::rgb(255, 255, 255),
+            background: None,
+            stroke: None,
+        },
+    );
+
+    assert!(opaque_pixels(&underlined_buffer) > opaque_pixels(&plain_buffer));
+}
+
+#[test]
+fn raster_stroke_widens_glyph_coverage() {
+    let mut engine = engine();
+    let measured = engine.measure(&params("Hello"), 180.0);
+    let fill_only = rasterize(
+        &mut engine,
+        &measured,
+        &RasterOptions {
+            text_color: Color::rgb(255, 255, 255),
+            background: None,
+            stroke: None,
+        },
+    );
+    let stroked = rasterize(
+        &mut engine,
+        &measured,
+        &RasterOptions {
+            text_color: Color::rgb(255, 255, 255),
+            background: None,
+            stroke: Some(StrokeStyle {
+                color: Color::rgb(0, 0, 0),
+                width: 4.0,
+            }),
+        },
+    );
+
+    assert!(opaque_pixels(&stroked) > opaque_pixels(&fill_only));
+}