Add Team Source

Register a git URL as a team-profile source so nyann can periodically sync and expose its profiles under a namespace. TRIGGER when the user says "add a team profile source", "register a team profile source", "set up team profiles from <url", "wire up our team's shared profiles at <repo", "add profile source named X at <url", "install team profiles from <git repo", "/nyann:add-team-source". Do NOT trigger on "sync team profiles now" (that's sync-team-profiles — the pull operation). Do NOT trigger on "save my setup as a profile" (that's learn-profile — writes to user root, not a team source). Do NOT trigger on generic "add a repo" or "add a remote" — those are git operations unrelated to profile distribution.