M4-4: L2 Disk Cache Implementation

Description

Add SQLite-based L2 disk cache for persistence across restarts.

Acceptance Criteria

• Add sqlite3 dependency
• Create disk cache at /tmp/mcp-cache.db
• 1GB maximum size limit
• TTL: 60-300 seconds based on data type
• Event-based invalidation on:
  • Container lifecycle events
  • Configuration file modifications
  • System reboot detection
  • Array operations

Technical Requirements

• Use Effect.Layer for disk cache service
• Implement as fallback to L1 memory cache
• Thread-safe SQLite operations
• Automatic vacuum on size limit

Estimated Effort

1 day