feat: implement always-adaptive caching with getCacheStats monitoring

Replaces lazy mode concept with always-adaptive caching strategy:

- Rename getLazyModeStats() → getCacheStats() with enhanced metrics
- Change lazyModeEnabled boolean → cachingStrategy enum ('preloaded' | 'on-demand')
- Update preloading threshold from 30% to 80% for better cache utilization
- Add comprehensive production monitoring and diagnostics
- Add memory detection for containers (Docker/K8s cgroups v1/v2)
- Add adaptive memory sizing from 2GB to 128GB+ systems

Breaking changes: None (backward compatible, deprecated lazy option ignored)

New APIs:
- getCacheStats(): Comprehensive cache performance statistics
- cachingStrategy field: Transparent strategy reporting
- Enhanced fairness metrics and memory pressure monitoring

Documentation:
- Add migration guide for v3.36.0
- Add operations/capacity-planning.md for enterprise deployments
- Update all examples and troubleshooting guides
- Rename monitor-lazy-mode.ts → monitor-cache-performance.ts

docs/vfs/QUICK_START.md

@@ -37,7 +37,7 @@ await vfs.init()
 console.log('🎉 VFS ready!')
 ```
 
-> **🚨 Common Mistake**: Don't use `storage: { type: 'memory' }` for file explorers - your data will disappear when the process exits!
+> **💡 Pro Tip**: Always use persistent storage (`filesystem`, `s3`, or `opfs`) for file explorers - your data persists across process restarts!
 
 ## 📁 Step 2: Safe Directory Listing (2 minutes)