Complete FileWatcher implementation using notify 8.x crate with get_inode() for cross-platform file identity. Support append detection for incremental index updates and truncate detection for full reloads. Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent) Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>