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, 21 insertions, 0 deletions

diff --git a/rust/crates/text/src/lib.rs b/rust/crates/text/src/lib.rs
index 8b137891..ccb324bf 100644
--- a/rust/crates/text/src/lib.rs
+++ b/rust/crates/text/src/lib.rs
@@ -1 +1,22 @@
+mod color;
+mod engine;
+mod layout;
+mod params;
+mod raster;
 
+pub use color::Color;
+pub use engine::{MeasuredTextLayout, TextEngine, TextError};
+pub use layout::{
+    LineMetrics, Rect, ResolvedTextLayout, STRIKETHROUGH_VERTICAL_RATIO,
+    TEXT_DECORATION_THICKNESS_RATIO, TextBlockMeasurement, align_offset, decoration_rect,
+    measure_text_block, resolve_text_layout, text_background_rect, text_rect, text_visual_rect,
+};
+pub use params::{
+    CORNER_RADIUS_MAX, CORNER_RADIUS_MIN, DEFAULT_BACKGROUND_COLOR,
+    DEFAULT_BACKGROUND_CORNER_RADIUS, DEFAULT_BACKGROUND_ENABLED, DEFAULT_BACKGROUND_OFFSET_X,
+    DEFAULT_BACKGROUND_OFFSET_Y, DEFAULT_BACKGROUND_PADDING_X, DEFAULT_BACKGROUND_PADDING_Y,
+    DEFAULT_LETTER_SPACING, DEFAULT_LINE_HEIGHT, DEFAULT_TEXT_COLOR, FONT_SIZE_SCALE_REFERENCE,
+    FontStyle, FontWeight, MAX_FONT_SIZE, MIN_FONT_SIZE, TextAlign, TextBackground, TextDecoration,
+    TextLayoutParams, text_background_from, text_layout_params_from,
+};
+pub use raster::{RasterOptions, RgbaBuffer, StrokeStyle, rasterize};