Release v0.3.0

Added

• Global Multi-Agent Support: Transitioned the layout of state.json to an isolated multi-agent format. Commands dynamically target specific agents, managing active presets and symlinks independently per agent.
• Commander --agent option: Introduced -a, --agent <agent...> native Commander variadic option in cli.js supporting space-separated lists and repeated flags (-a replit aider-desk -a universal), matching the original utility.
• Dynamic Multi-Agent Actions: Overhauled usePresets(), syncState(), collect(), and showStatus() to run dynamically based on targeted agents or globally across all 50+ configured agent directories.
• Cleaned Public API: Completely encapsulated low-level syncState and testing helpers into the private tests namespace in index.js, keeping the main exported API lightweight and focused on standard user commands.
• Agent Key Validation: collect(), showStatus(), and usePresets() now validate every supplied -a agent key against the SUPPORTED_AGENTS registry. An unrecognised key (including comma-joined strings such as replit,aider-desk) immediately prints Error: Invalid agent: <agent> to stderr and exits with code 1.