feat(ai): Expose FlatRun's tools as an MCP server

[nfebe]

FlatRun should expose its own MCP server whose tools are the same set the assistant can call. Anything an operator can do through the assistant they can then also do from any MCP client, and the reverse: practically anything on the server, bounded only by the caller's permissions. The assistant and the MCP server are two front doors onto one tool set, not two tool sets.

Checklist

• Make the assistant's tools the single source of truth (built-in plus plugin tools), shared by the assistant and the MCP server rather than duplicated.
• Serve an MCP endpoint that advertises that tool set and executes calls against the same handlers.
• Authenticate and authorize an MCP caller with the same actor model and per-deployment permissions the assistant uses; a caller only sees and runs the tools its access allows.
• Gate mutating tools identically whether the call arrives from the assistant or MCP: deployment-write, protected mode, and approval where it applies.
• Persist MCP access (tokens and scopes) in the credential manager; surface enable/disable and a connection guide in the UI.
• Later, optionally, an MCP client so the assistant can also use external MCP servers' tools.

Related

• feat(ai): Add more tools for quick actions, file editing, summarization etc #147 (more assistant tools; each new tool becomes part of the shared set exposed here)