refactor(cli): unify daemon into multica-cli binary with cobra subcommands

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) <noreply@anthropic.com>

.gitignore

@@ -24,6 +24,7 @@ server/bin/
 server/tmp/
 server/migrate
 server/daemon
+server/multica-cli
 
 # Test artifacts
 test-results/