fix: include submodule files in file search

[he-yufeng]

Summary

• include tracked files inside submodules in the git-backed file crawler
• keep the existing skip for the submodule gitlink itself
• add a regression test that requires git ls-files --cached --recurse-submodules

Fixes #4568

To verify

• npm exec -- vitest run packages/core/src/utils/filesearch/crawler.test.ts
• npm exec -- eslint packages/core/src/utils/filesearch/crawler.ts packages/core/src/utils/filesearch/crawler.test.ts --max-warnings 0
• npm exec -- prettier --check packages/core/src/utils/filesearch/crawler.ts packages/core/src/utils/filesearch/crawler.test.ts
• npm run typecheck --workspace=@qwen-code/qwen-code-core

[wenshao]

[Suggestion] The test asserts that the submodule file is included in results, but doesn't assert the negative: that the submodule gitlink entry (packages/nested) itself is excluded. The mock data already sets up this scenario (S packages/nested), and the production code correctly filters S-status entries — but without a negative assertion, a regression in S-status filtering would go undetected.

Suggested change

	expect(results).toContain('packages/nested/submodule-file.ts');
	expect(cachedGitCall).toContain('--recurse-submodules');
	expect(results).toContain('packages/nested/submodule-file.ts');
	expect(results).not.toContain('packages/nested');

— qwen3.7-max via Qwen Code /review

[he-yufeng]

Added the negative assertion from the review so the test now also verifies that the submodule gitlink entry itself is not returned.

Re-ran:

• npm exec -- vitest run packages/core/src/utils/filesearch/crawler.test.ts -t "submodule"
• git diff --check -- packages/core/src/utils/filesearch/crawler.test.ts

[wenshao]

[Suggestion] --recurse-submodules is added to the --cached listing but git does not support it with --deleted (exits 128: fatal: ls-files --recurse-submodules unsupported mode). This creates a known asymmetry: a tracked-then-deleted file inside a submodule appears in the --cached --recurse-submodules output but cannot be filtered by deletedSet (populated from listDeletedTrackedFiles), resulting in a phantom entry in search results.

The practical impact is narrow (deleting tracked files inside submodules is uncommon), and the fix is non-trivial (would require per-submodule enumeration). Adding a brief code comment documenting this known limitation would help future maintainers who might otherwise attempt the same --recurse-submodules fix on the --deleted path and hit the git error.

Suggested change

	'--recurse-submodules',
	const trackedArgs = [
	'--literal-pathspecs',
	'ls-files',
	'--cached',
	// NOTE: --recurse-submodules is only supported for --cached/--stage.
	// listDeletedTrackedFiles cannot use it, so a tracked file deleted
	// inside a submodule may appear as a phantom entry in results.
	'--recurse-submodules',
	];

— qwen3.7-max via Qwen Code /review

[he-yufeng]

Closing this duplicate path in favor of #4596, which already has the fuller submodule fix and maintainer verification. Thanks for reviewing both.