Watch file changes for automatic import

[sanggggg]

Description

Implement file system watching to automatically detect and import new chat history files as they are created or modified.

Context

Currently, users need to manually run import commands when new chat files are available. Automatic watching would provide a better user experience and ensure chat history stays up-to-date.

Proposed Implementation

• Use file system watching library (e.g., notify-rs)
• Monitor configured provider directories
• Automatically trigger import when new files are detected
• Handle file modifications and updates gracefully
• Add configuration options for watch behavior

Benefits

• Real-time chat history synchronization
• Reduced manual intervention
• Better user experience

[tantara]

watch and parse #13
import TODO