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/troubleshooting.md

@@ -77,15 +77,10 @@ chmod 755 ./brainy-data
 # Use custom writable path
 const brain = new Brainy({
   storage: {
-    adapter: 'filesystem',
+    type: 'filesystem',
     path: '/tmp/brainy-data'
   }
 })
-
-# Or use memory storage
-const brain = new Brainy({
-  storage: { forceMemoryStorage: true }
-})
 ```
 
 ### "ENOENT: no such file or directory"
@@ -100,7 +95,7 @@ mkdir -p ./brainy-data
 # Check storage configuration
 const brain = new Brainy({
   storage: {
-    adapter: 'filesystem',
+    type: 'filesystem',
     path: '/full/path/to/storage' // Use absolute path
   }
 })
@@ -280,11 +275,11 @@ const brain = new Brainy({
      run: npm test
    ```
 
-2. **Use memory storage in tests**
+2. **Use temporary filesystem storage in tests**
    ```typescript
    // In test setup
    const brain = new Brainy({
-     storage: { forceMemoryStorage: true }
+     storage: { type: 'filesystem', path: '/tmp/brainy-test' }
    })
    ```