fix(dart): an annotation links the constant or constructor it names, even behind a comment (#2390)

A Dart annotation is a constant expression: a const variable (`@riverpod`,
`@meta.immutable`, a type's static constant or enum value) or a call of a
const constructor (`@Riverpod(keepAlive: true)`, `@Foo.named(…)`). It was
ranked like a Python decorator, which favours a function or method of that
name over a class and scores a constant not at all, so riverpod's 506
`@riverpod` annotations went to riverpod_analyzer_utils' extension getter
`riverpod` (0.4) instead of riverpod_annotation's `const riverpod = Riverpod();`.

matchDartAnnotation (name-matcher.ts) now takes every Dart `decorates` ref
before any other strategy, and nothing falls through. It reads the
annotation as written from its `@` and links a constant or (called) a class
the file's library can see, through the import prefix it is written with
(isDartImportPrefix, dart-libraries.ts); a type's own static constant, enum
value or (called) named constructor (isDartConstructor); or, on a member, a
static constant of the type around it. Never a method, getter or function.

The decorator scan also stopped at the first sibling that was not an
annotation, so a comment between an annotation and its declaration
(`@override` `// ignore: must_call_super` `void f()`, riverpod_lint's
`@riverpod` `// expect_lint: …` fixtures) hid the annotation. Dart's
decoratorStepOverTypes lists its two comment kinds, which the scan now
steps over, and the kernel's extract_decorators_for steps over the same.

Validated on rrousselGit/riverpod @4ba1be2 and felangel/bloc @b9be1e2 with
the kernel loaded: riverpod's 506 `@riverpod` edges move to `const riverpod`
and 16 annotations behind a comment add an edge each, with nothing removed;
bloc gains 7 `@override` refs and no edge changes. Kernel and wasm full-index
dumps are byte-identical, and the parity sweeps show 0 diffs.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

codegraph-kernel/src/dart.rs

@@ -51,6 +51,12 @@ const MAX_VALUE_REF_NODES: usize = 20_000;
 /// `Widget build(…)`), so the docstring walk steps over them.
 const DOCSTRING_STEP_OVER: &[&str] = &["annotation"];
 
+/// decoratorStepOverTypes (dart.ts) — an annotation belongs to the next
+/// declaration, whatever comments come between them (`@override`
+/// `// ignore: must_call_super` `void f()`), so the decorator scan steps over
+/// them.
+const DECORATOR_STEP_OVER: &[&str] = &["comment", "documentation_comment"];
+
 /// NAME_STOPLIST (function-ref.ts).
 fn is_stoplisted(name: &str) -> bool {
     matches!(
@@ -1457,7 +1463,8 @@ impl<'t> Walker<'t> {
         }
         // Scan 2: preceding siblings, backward, stop at the first
         // non-annotation — stacked annotations emit in REVERSE source order.
-        // A `declaration`-wrapped member's annotations precede the wrapper.
+        // A `declaration`-wrapped member's annotations precede the wrapper,
+        // and the comments between annotations and declaration are stepped over.
         let anchor = self.declaration_wrapper(decl).unwrap_or(decl);
         if let Some(parent) = anchor.parent() {
             let decl_start = anchor.start_byte();
@@ -1473,6 +1480,9 @@ impl<'t> Walker<'t> {
             if let Some(di) = decl_idx {
                 for j in (0..di).rev() {
                     let Some(sib) = parent.named_child(j) else { continue };
+                    if DECORATOR_STEP_OVER.contains(&sib.kind()) {
+                        continue;
+                    }
                     if !matches!(sib.kind(), "decorator" | "annotation" | "marker_annotation") {
                         break;
                     }