Add standalone MCP shell server

[tg1482]

Summary

• add a standalone mcp/ uv project for a shell MCP server
• include policy loading, command allow/deny checks, and output truncation
• provide a default policy template for local development

Testing

• not run (not requested)

[tg1482]

we dont even have git and rg and uv commands wtf. what is this for?

[tg1482]

our shellpolicy here is very limited to just the shell commands that we support baesd on README - make suer thats respected

[tg1482]

how will this change now that we have a file backed feature?

[tg1482]

Simplified the policy: removed deny/env sections, switched to a single list aligned to the README shell commands, and dropped env overrides in the server (uses process env). Re: file-backed Loopy — not wired into this MCP server yet; that would be a separate MCP tool that calls against a path. Happy to add that in a follow-up if you want it here.

[tg1482]

Simplified the policy: removed deny/env sections, switched to a single allowed_commands list aligned to the README shell commands, and dropped env overrides in the server (uses process env).

Re: file-backed Loopy — not wired into this MCP server yet; that would be a separate MCP tool that calls loopy.shell.run against a FileBackedLoopy path. Happy to add that in a follow-up if you want it here.