feat(ie-css): implement style resolution pipeline #23

resolve.rs: walks DOM tree depth-first, produces ResolvedStyle per node:
- Calls cascade() for each element with UA + author stylesheets
- Applies inline styles as highest priority override
- Resolves 53 properties: cascaded → inherited → initial → computed
- compute_value: em (parent font-size), rem (16px root), vw/vh
  (viewport), vmin/vmax, pt (4/3 px ratio) → absolute px
- ResolvedStyle with get(), display(), get_length_px(), get_color()
- ViewportSize parameter (default 1920x1080)
- Inheritance: inherited properties propagate from parent
- initial/inherit/initial keywords handled

12 new tests: color, inheritance, non-inheritance, em/rem/viewport
resolution, UA defaults, inline override, deep chain, initial values.
85 total ie-css tests.

Author: thomasnemer

crates/ie-css/src/lib.rs

@@ -5,13 +5,15 @@
 
 pub mod cascade;
 pub mod parser;
+pub mod resolve;
 pub mod selector;
 pub mod style;
 pub mod tokenizer;
 pub mod values;
 
 pub use cascade::cascade;
 pub use parser::{Declaration, Rule, Stylesheet, parse_declarations, parse_stylesheet};
+pub use resolve::{ResolvedStyle, ViewportSize, resolve_styles};
 pub use selector::{
     Selector, Specificity, matches as selector_matches, parse_selector, parse_selector_list,
     specificity,