fix(doctor): respect max_file_size when walking project files

[shixi-li]

Summary

• pass the project's max_file_size setting into Doctor's file matcher
• add a regression covering the inclusive size boundary, oversized-file exclusion, and the no-limit fallback

Why

max_file_size is part of the project matching contract introduced in #248. Indexing and ccc grep already pass it to build_matcher, but Doctor's File Walk check omitted the fourth argument. As a result, ccc doctor could report oversized files as matched even though indexing and grep correctly skipped them.

This keeps Doctor's preview consistent with the files the rest of the project actually processes.

Validation

• .venv/bin/pytest tests/test_daemon.py::test_file_walk_respects_project_max_file_size tests/test_file_walk.py -k 'file_walk_respects_project_max_file_size or max_file_size' -q — 4 passed
• .venv/bin/ruff check src/cocoindex_code/daemon.py tests/test_daemon.py
• .venv/bin/ruff format --check src/cocoindex_code/daemon.py tests/test_daemon.py
• .venv/bin/mypy src/cocoindex_code/daemon.py

The locked full dev extra cannot be installed on this macOS x86_64 host because torch==2.13.0 has no compatible wheel; the focused tests above use the base dependency set, and CI can exercise the repository's full Linux matrix.

[badmonster0]

thanks @shixi-li , @georgeh0 can help take a look!