feat(highlight): implement tree-house syntax highlighting engine

Replace tree-sitter-highlight with Helix's tree-house crate for
advanced syntax highlighting:

- Add tree-house and tree-house-bindings dependencies
- Implement SukrLoader with LanguageLoader trait
- Add hierarchical scope resolution with fallback
  (e.g., keyword.control.conditional → keyword.control → keyword)
- Create custom HTML renderer processing HighlightEvents
- Support all 14 languages with Helix queries
- Handle JS/TS inheritance chain (ecma → _javascript/_typescript)

Benefits:
- Richer semantic highlighting with ~75 scope classes
- Proper language injection support
- Hierarchical theme scopes matching Helix themes
- Foundation for converting Helix TOML themes to CSS

Cargo.lock

@@ -418,12 +418,6 @@ version = "1.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "abd57806937c9cc163efc8ea3910e00a62e2aeb0b8119f1793a978088f8f6b04"
 
-[[package]]
-name = "diff"
-version = "0.1.13"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "56254986775e3233ffa9c4d7d3faaf6d36a2c09d30b20687e9f88bc8bafc16c8"
-
 [[package]]
 name = "digest"
 version = "0.10.7"
@@ -520,7 +514,7 @@ version = "0.2.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cfe4fbac503b8d1f88e6676011885f34b7174f46e59956bba534ba83abded4df"
 dependencies = [
- "unicode-width 0.2.2",
+ "unicode-width",
 ]
 
 [[package]]
@@ -1150,16 +1144,6 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "925383efa346730478fb4838dbe9137d2a47675ad789c546d150a6e1dd4ab31c"
 
-[[package]]
-name = "pretty_assertions"
-version = "1.4.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3ae130e2f271fbc2ac3a40fb1d07180839cdbbe443c7a27e1e3c13c5cac0116d"
-dependencies = [
- "diff",
- "yansi",
-]
-
 [[package]]
 name = "prettyplease"
 version = "0.2.37"
@@ -1626,6 +1610,7 @@ dependencies = [
  "thiserror 2.0.18",
  "toml 0.8.23",
  "tree-house",
+ "tree-house-bindings",
  "tree-sitter",
  "tree-sitter-bash",
  "tree-sitter-c",
@@ -1821,13 +1806,11 @@ dependencies = [
  "hashbrown 0.15.5",
  "kstring",
  "once_cell",
- "pretty_assertions",
  "regex",
  "regex-cursor",
  "ropey",
  "slab",
  "tree-house-bindings",
- "unicode-width 0.1.12",
 ]
 
 [[package]]
@@ -1840,6 +1823,7 @@ dependencies = [
  "regex-cursor",
  "ropey",
  "thiserror 2.0.18",
+ "tree-sitter-language",
 ]
 
 [[package]]
@@ -2041,12 +2025,6 @@ version = "1.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f6ccf251212114b54433ec949fd6a7841275f9ada20dddd2f29e9ceea4501493"
 
-[[package]]
-name = "unicode-width"
-version = "0.1.12"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "68f5e5f3158ecfd4b8ff6fe086db7c8467a2dfdac97fe420f2b7c4aa97af66d6"
-
 [[package]]
 name = "unicode-width"
 version = "0.2.2"
@@ -2257,12 +2235,6 @@ dependencies = [
  "hashlink",
 ]
 
-[[package]]
-name = "yansi"
-version = "1.0.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cfe53a6657fd280eaa890a3bc59152892ffa3e30101319d168b781ed6529b049"
-
 [[package]]
 name = "zerocopy"
 version = "0.8.33"