feat: add complete silent mode for TUI applications

- Add silent option to BrainyConfig to suppress ALL console output
- Override console methods (log, info, warn, error) when silent=true
- Add LogLevel.SILENT to Logger for proper silent mode support
- Propagate silent mode to all augmentations automatically
- Update augmentation configs to support silent property
- Restore console methods properly on brain.close()
- Perfect for terminal UI applications that need clean output

Usage:
```javascript
const brain = new Brainy({
  storage: { type: 'filesystem', path: './data' },
  silent: true  // Complete silence - zero console output
})
```

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/augmentations/cacheAugmentation.ts

@@ -18,6 +18,7 @@ export interface CacheConfig {
   ttl?: number
   enabled?: boolean
   invalidateOnWrite?: boolean
+  silent?: boolean  // Silent mode support
 }
 
 /**
@@ -80,6 +81,11 @@ export class CacheAugmentation extends BaseAugmentation {
             type: 'boolean',
             default: true,
             description: 'Automatically invalidate cache on data modifications'
+          },
+          silent: {
+            type: 'boolean',
+            default: false,
+            description: 'Suppress all console output'
           }
         },
         additionalProperties: false