Allow reloading MCP servers without restarting the session

Feature Request

Problem: MCP servers are loaded once at session startup. If you add, remove, or modify MCP server configurations in .mcp.json mid-session, there is no way to pick up those changes without exiting and restarting the entire session. This breaks flow, especially when iterating on MCP server configs or adding new servers while working.

Proposed Solution: Add a command (e.g., /mcp-reload or /reload-servers) that re-reads .mcp.json and reconnects MCP servers without restarting the session. This would:

• Detect added/removed/changed server entries in .mcp.json
• Start newly added servers
• Stop removed servers
• Reconnect modified servers

Use Case: As a user who configures multiple MCP servers (10+), I frequently add or adjust servers based on the work at hand. Having to restart the session each time loses conversation context and interrupts workflow.