Extract daemon logic from cmd/daemon/ into internal/daemon/ package and
create a new unified CLI entry point at cmd/multica/ using cobra. The CLI
supports `daemon` as a long-running subcommand plus ctrl subcommands for
agent/runtime management, config, status, and version.
Server, migrate, and seed binaries remain unchanged.
Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>
