fix(go): handle chan T return types and tighten GOPATH suffix resolution

- Strip 'chan ' prefix in return-type qualification loop so that
  func Events() chan Event does not emit pkg.chan Event (H2 edge case)
- Require ≥2 path segments in GOPATH fallback to avoid false-positive
  matches when an external import suffix collides with a local directory
  named pkg/, util/, internal/, etc. (review H1)
- Add import resolution tests for module sub-package, single-segment
  collision rejection, and multi-segment GOPATH match

gitnexus/src/core/ingestion/languages/go/captures.ts

@@ -180,7 +180,9 @@ export function emitGoScopeCaptures(
       let raw = typeCap.text.trim();
       while (raw.startsWith('*')) raw = raw.slice(1).trim();
       if (raw.startsWith('[]')) raw = raw.slice(2).trim();
+      if (raw.startsWith('chan ')) raw = raw.slice(5).trim();
       if (raw.includes('.') || raw.startsWith('func(') || raw.startsWith('map[')) continue;
+      if (raw.startsWith('chan ')) continue;
       if (GO_BUILTIN_TYPES.has(raw)) continue;
       const idx = raw.indexOf('[');
       if (idx !== -1) raw = raw.slice(0, idx);

gitnexus/src/core/ingestion/languages/go/import-target.ts

@@ -37,10 +37,12 @@ export function resolveGoImportTarget(
     if (files.length > 0) return files;
   }
 
-  // 2) Non-go.mod / GOPATH: progressively shorter directory suffixes
-  //    "github.com/xxx/yyy/pkg" → try "github.com/xxx/yyy/pkg/" → "xxx/yyy/pkg/" → "yyy/pkg/" → "pkg/"
+  // 2) Non-go.mod / GOPATH: progressively shorter directory suffixes.
+  //    "github.com/xxx/yyy/pkg" → try "github.com/xxx/yyy/pkg/" → "xxx/yyy/pkg/" → "yyy/pkg/"
+  // Stop at ≥2 segments to avoid matching a single-segment suffix (e.g.
+  // "pkg", "util", "internal") to a local directory with the same name.
   const parts = targetRaw.split('/').filter(Boolean);
-  for (let i = 0; i < parts.length; i++) {
+  for (let i = 0; i < parts.length - 1; i++) {
     const files = findAllFilesInPkgDir(allFilePaths, parts.slice(i).join('/'));
     if (files.length > 0) return files;
   }

gitnexus/test/unit/scope-resolution/go/go-imports.test.ts

@@ -111,4 +111,45 @@ describe('Go import target resolution', () => {
 
     expect(result).toEqual(['extra.go', 'root.go']);
   });
+
+  it('resolves sub-package imports under module root', () => {
+    const result = resolveGoImportTarget(
+      'example.com/lib/internal/models',
+      'cmd/app/main.go',
+      new Set(['internal/models/user.go', 'internal/models/repo.go', 'root.go']),
+      { modulePath: 'example.com/lib' },
+    );
+
+    expect(Array.isArray(result)).toBe(true);
+    expect((result as string[]).sort()).toEqual([
+      'internal/models/repo.go',
+      'internal/models/user.go',
+    ]);
+  });
+
+  it('rejects single-segment GOPATH suffix that collides with a local dir', () => {
+    // "github.com/other/team/pkg" suffix-stripped would eventually
+    // reach "pkg" which matches the local pkg/ dir — but we require
+    // ≥2 segments in the GOPATH fallback, so it must not resolve.
+    const result = resolveGoImportTarget(
+      'github.com/other/team/pkg',
+      'main.go',
+      new Set(['pkg/util.go', 'main.go']),
+    );
+
+    expect(result).toBeNull();
+  });
+
+  it('resolves multi-segment GOPATH suffix that matches local dir', () => {
+    // "github.com/other/team/pkg" where "team/pkg/" exists locally
+    // — the 2-segment suffix "team/pkg" should still resolve.
+    const result = resolveGoImportTarget(
+      'github.com/other/team/pkg',
+      'main.go',
+      new Set(['team/pkg/util.go', 'main.go']),
+    );
+
+    expect(Array.isArray(result)).toBe(true);
+    expect(result as string[]).toEqual(['team/pkg/util.go']);
+  });
 });