fix: highlight PHP attributes as decorators

Attribute usages need a semantic token distinct from normal class references so editor themes can color #[...] separately from classes used in types or expressions. Reuse the existing attribute class-reference context to emit the standard decorator token.\n\nCloses #117

Author: calebdw

docs/CHANGELOG.md

@@ -42,6 +42,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- **PHP attributes use decorator semantic highlighting.** Attribute class names in `#[...]` now emit the `decorator` semantic token instead of `class`, so editor themes can color attributes differently from normal class references. Contributed by @calebdw.
 - **Go-to-definition on overriding methods jumps to the parent declaration.** When the cursor is on a method definition that overrides a parent or implements an interface method, go-to-definition now navigates to the prototype declaration instead of returning call-site references. Similarly, go-to-definition on a class name jumps to the parent class when one exists. Methods and classes that don't override anything still show usages as before. Contributed by @calebdw.
 - **Go-to-definition on overridden properties and constants jumps to the prototype declaration.** Declaration-site navigation now follows overridden properties and constants to the nearest parent or trait declaration, matching the override behavior for methods. Contributed by @calebdw.
 - **Code lens navigation works on Cursor, VSCodium, Neovim, and other editors.** Clicking a code lens annotation (e.g. "overrides Parent::method") now uses the standard `window/showDocument` LSP request instead of editor-specific commands (`vscode.open`, `editor.action.showReferences`) that only worked on VS Code. Contributed by @calebdw.

src/semantic_tokens.rs

@@ -21,7 +21,7 @@ use tower_lsp::lsp_types::*;
 
 use crate::Backend;
 use crate::diagnostics::unknown_members::member_exists;
-use crate::symbol_map::{SelfStaticParentKind, SymbolKind, SymbolMap, VarDefKind};
+use crate::symbol_map::{ClassRefContext, SelfStaticParentKind, SymbolKind, SymbolMap, VarDefKind};
 use crate::types::{ClassInfo, ClassLikeKind};
 
 // ─── Token type indices ─────────────────────────────────────────────────────
@@ -258,7 +258,9 @@ impl Backend {
                     // already highlights the import prolog per name segment;
                     // a single token spanning the whole path (backslashes
                     // included) would visibly override that coloring.
-                    if *context == crate::symbol_map::ClassRefContext::UseImport {
+                    if *context == ClassRefContext::Attribute {
+                        (TT_DECORATOR, 0)
+                    } else if *context == ClassRefContext::UseImport {
                         if !is_blade {
                             continue;
                         }

tests/integration/semantic_tokens.rs

@@ -30,6 +30,7 @@ const TT_VARIABLE: u32 = 7;
 const TT_PROPERTY: u32 = 8;
 const TT_FUNCTION: u32 = 9;
 const TT_METHOD: u32 = 10;
+const TT_DECORATOR: u32 = 11;
 #[allow(dead_code)]
 const TT_ENUM_MEMBER: u32 = 12;
 #[allow(dead_code)]
@@ -227,6 +228,28 @@ function make() {
     );
 }
 
+#[test]
+fn attribute_class_reference_uses_decorator_token() {
+    let php = r#"<?php
+#[MyAttribute]
+class Example {}
+
+new MyAttribute();
+
+class MyAttribute {}
+"#;
+    let tokens = get_tokens(php);
+    let decoded = decode_tokens(&tokens);
+
+    let attribute = find_decoded(&decoded, 1, 2).expect("expected token for attribute class");
+    assert_eq!(attribute.token_type, TT_DECORATOR);
+    assert_eq!(attribute.length, 11);
+
+    let new_expression = find_decoded(&decoded, 4, 4).expect("expected token for class reference");
+    assert_eq!(new_expression.token_type, TT_CLASS);
+    assert_eq!(new_expression.length, 11);
+}
+
 #[test]
 fn variable_tokens() {
     let php = r#"<?php