v0.4.5

Enables duho's MCP launch trigger, which 0.4.4 had turned off. No other change.

Changed

• MCP is enabled. With AUTHKEYS_MCP=stdio set, authkeys now serves
  its commands (resolve, check, serve, cache, completion) as MCP
  tools over stdio, which is duho's default launch trigger. 0.4.4 opted the
  whole CLI out. These tools return real authorized_keys content, and
  serve starts a listener, so only set the variable for an MCP client you
  trust. Without the variable, the CLI behaves exactly as before.

Full Changelog: v0.4.4...v0.4.5