fix: agent_run param mismatch (send agent_name) + add GitHub push-update (3 inputs: repo name, token, username; --force-with-lease)

feat: add GitHub project import + fix Agent tab scroll (shallow clone, heavy-dir stripping, /github slash command, UI box)

feat(agent): add Claude Code-style agent, skills, slash-commands, hooks, todos, sandboxed workspace, and full-stack scaffolding