v2.1.0

🏗️ Async support for MultipleInstanceManager

• instanceAsync(name) — async resolution with built-in deduplication
• createDriverAsync(driver, config) — override for async driver creation
• setInstance(name, instance) — manual cache population
• hasInstance(name) — check if cached (replaces hasResolvedInstance)
• Pending map prevents duplicate async resolutions
• Updated mixin to match base class API
• Fixed tsconfig for TS 6.0 compatibility