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, 74 insertions, 0 deletions

diff --git a/rust/crates/animation/src/lib.rs b/rust/crates/animation/src/lib.rs
index 8b137891..01f64b57 100644
--- a/rust/crates/animation/src/lib.rs
+++ b/rust/crates/animation/src/lib.rs
@@ -1 +1,75 @@
+mod bezier;
+mod channel_data;
+mod channel_layout;
+mod color;
+mod effect_param_channel;
+mod graph_channels;
+mod graphic_param_channel;
+mod id;
+mod interpolation;
+mod keyframe_query;
+mod keyframes;
+mod params;
+mod path;
+mod property_groups;
+mod resolve;
+mod types;
+mod values;
 
+pub use bezier::{
+    BEZIER_SOLVE_ITERATIONS, BezierHandle, bezier_point, default_left_handle,
+    default_right_handle, segment_handles, solve_bezier_progress_for_time,
+};
+pub use channel_data::{
+    get_channel_entries_from_data, get_channels_from_data, is_animation_storage_key,
+    ordered_composite_entries,
+};
+pub use channel_layout::{
+    ChannelComponentDefinition, ChannelLayout, ChannelValueKind, boolean_channel_layout,
+    color_channel_layout, number_channel_layout, string_channel_layout,
+};
+pub use color::{LinearRgba, format_linear_rgba, parse_color_to_linear_rgba};
+pub use effect_param_channel::{
+    EFFECT_PARAM_PATH_PREFIX, EFFECT_PARAM_PATH_SUFFIX, build_effect_param_path,
+    is_effect_param_path, parse_effect_param_path, remove_effect_param_keyframe,
+    resolve_effect_params_at_time,
+};
+pub use graph_channels::{
+    ChannelEasingMode, EditableScalarChannels, ScalarGraphChannel, ScalarGraphKeyframeContext,
+    get_editable_scalar_channel, get_editable_scalar_channels, get_scalar_keyframe_context,
+};
+pub use graphic_param_channel::{
+    GRAPHIC_PARAM_PATH_PREFIX, build_graphic_param_path, is_graphic_param_path,
+    parse_graphic_param_path, resolve_graphic_params_at_time,
+};
+pub use id::generate_uuid;
+pub use interpolation::{
+    channel_value_at_time, discrete_channel_value_at_time, is_scalar_channel, normalize_channel,
+    normalize_discrete_channel, normalize_scalar_channel, scalar_channel_value_at_time,
+    scalar_segment_interpolation,
+};
+pub use keyframe_query::{
+    get_element_keyframes, get_keyframe_at_time, get_keyframe_by_id, has_keyframes_for_path,
+};
+pub use keyframes::{
+    SplitChannelResult, clamp_animations_to_duration, clone_animations, get_channel,
+    remove_element_keyframe, remove_keyframe, retime_element_keyframe, retime_keyframe,
+    set_binding_component_channel, set_channel, split_animations_at_time,
+    split_animations_at_time_with_options, to_animation, update_scalar_keyframe_curve,
+    upsert_discrete_channel_key, upsert_keyframe, upsert_path_keyframe, upsert_scalar_channel_key,
+};
+pub use params::{
+    NumberParamDefinition, ParamDefinition, ParamValueKind, SelectOption, coerce_param_value,
+    get_param_channel_layout, get_param_default_interpolation, get_param_numeric_range,
+    get_param_value_kind, snap_to_step,
+};
+pub use path::is_animation_path;
+pub use property_groups::{
+    ANIMATION_PROPERTY_GROUPS, GroupKeyframeRef, animation_property_group_paths,
+    get_group_keyframes_at_time, has_group_keyframe_at_time, is_animation_property_path,
+};
+pub use resolve::{get_element_local_time, resolve_animation_path_value_at_time};
+pub use types::{
+    AnimationInterpolation, ElementKeyframe, NumericSpec, ScalarCurveKeyframePatch,
+};
+pub use values::{resolve_color_at_time, resolve_number_at_time, resolve_opacity_at_time};