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/architecture/storage-architecture.md

@@ -68,18 +68,6 @@ const brain = new Brainy({
 - **Performance**: Near-native file system speed
 - **Persistence**: Permanent in browser (with quota limits)
 
-### Memory Storage
-```typescript
-const brain = new Brainy({
-  storage: {
-    type: 'memory'
-  }
-})
-```
-- **Use case**: Testing, temporary processing
-- **Performance**: Fastest possible
-- **Persistence**: Volatile (lost on restart)
-
 ## Metadata Indexing System
 
 ### Field Discovery Index
@@ -284,14 +272,15 @@ console.log(stats)
 ## Best Practices
 
 ### Choose the Right Adapter
-1. **Development**: Memory or FileSystem
+1. **Development**: FileSystem (local persistence)
 2. **Production Server**: FileSystem or S3
-3. **Browser Apps**: OPFS or Memory
+3. **Browser Apps**: OPFS
 4. **Distributed**: S3 with caching
 
 ### Optimize for Your Use Case
 1. **Read-heavy**: Enable aggressive caching
-3. **Real-time**: Memory with periodic persistence
+2. **Write-heavy**: Batch operations
+3. **Real-time**: FileSystem with periodic snapshots
 4. **Archival**: S3 with compression
 
 ### Monitor and Maintain