test+feat: add cargo workspace crate resolution for rust resolver (#151)

* test+feat: add cargo workspace crate resolution for rust resolver

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* perf: cache cargo workspace map during rust resolution

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* feat(rust): expand cargo workspace member globs and trust workspace hits

- Parse glob entries in `[workspace].members` (e.g. `crates/*`,
  `helix-*`) via picomatch against a new optional
  `ResolutionContext.listDirectories` so workspaces that don't
  enumerate every member are covered. Implementation walks the
  static-prefix subtree with a depth cap and skips `target`,
  `node_modules`, `.git`, etc.
- Bump Pattern 4's confidence to 0.95 when the workspace map
  produces a hit. The cargo manifest gives an unambiguous
  crate-name -> crate-root mapping, so workspace-driven module
  resolution should beat name-matcher's self-file matches
  (otherwise every file with `use foo::...` self-resolves at 0.7
  and the cross-crate edge never materializes).
- Validated against astral-sh/uv (`members = ["crates/*"]`,
  67 crates, 567 .rs files): 1,969 cross-crate `imports` edges
  reaching 60 distinct member lib.rs files, up from 0.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Colby McHenry <me@colbymchenry.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/resolution/types.ts

@@ -98,6 +98,15 @@ export interface ResolutionContext {
    * re-export chains when this is provided.
    */
   getReExports?(filePath: string, language: Language): ReExport[];
+  /**
+   * List immediate subdirectories of `relativePath` (relative to the
+   * project root). Returns an empty array when the path doesn't exist
+   * or isn't a directory. Used by framework resolvers that need to
+   * walk build-system metadata (e.g. Cargo workspace globs). Optional
+   * so external context implementations and test fixtures compile
+   * without modification.
+   */
+  listDirectories?(relativePath: string): string[];
 }
 
 /**