feat: --auto-watch flag to embed watcher inside MCP server process

[Dhruv-Darji]

This pull request adds robust offline daemon support and improves the CLI and server integration for the code review graph tool. The main enhancements include a new daemon command for managing a background filesystem watcher, improved serve/mcp command wiring with optional auto-watch, and extensive internal refactoring for process management and status reporting. Comprehensive tests for the new CLI commands and daemon helpers are also included.

CLI and Daemon Command Enhancements:

• Added a new daemon command to the CLI for starting, stopping, and checking the status of an offline watch daemon, including support for foreground/background operation and status metadata. (code_review_graph/cli.py, code_review_graph/incremental.py) [1] [2] [3] [4]
• Updated the CLI to support serve and mcp commands with an --auto-watch flag, allowing the MCP server to run alongside a background file watcher. (code_review_graph/cli.py, code_review_graph/main.py) [1] [2] [3] [4]

Daemon Process Management and Watcher Refactoring:

• Implemented process management helpers for daemon lifecycle: PID/lock/log file handling, cross-platform process checks, and clean startup/shutdown logic. (code_review_graph/incremental.py) [1] [2]
• Refactored the watcher to enforce a single-writer lock using PID files, with robust acquisition/release and error handling. (code_review_graph/incremental.py)
• Added support for running the watcher in a background thread for integration with the MCP server, and provided helpers for starting/stopping/status reporting of the daemon. (code_review_graph/incremental.py, code_review_graph/main.py) (Fa10b2a3L933, code_review_graph/main.pyL690-R714)

Testing Improvements:

• Added new tests for CLI command wiring, including serve, mcp, and all daemon subcommands, as well as tests for the new daemon helpers and lock acquisition logic. (tests/test_cli.py, tests/test_incremental.py) [1] [2] [3]

These changes make the tool more robust for offline and background operation, and provide a more user-friendly and scriptable interface for managing the file watcher and MCP server.

[tirth8205]

Interesting feature — embedding a file watcher inside the MCP server process. This is a significant addition (+657 lines) with PID/lock file management and daemon lifecycle.

A few concerns:

1. Cross-platform PID handling needs careful testing (Windows, WSL).
2. Lock file cleanup on crash — what happens if the process dies without cleaning up?
3. This overlaps with the existing watch command — how do they interact?

Please rebase on latest main and address these questions. We'll give it a thorough review once it's up to date.