fix(typescript): resolve compilation errors for production build

Fixes 4 TypeScript compilation errors preventing successful build:

## Errors Fixed

### 1. lid-mapping.ts:799 - Property 'metricsModule' does not exist
**Error**: `this.metricsModule = null` in destroy() but property never declared
**Fix**: Removed orphaned line from previous metrics cleanup
**Impact**: Allows successful compilation

### 2-3. socket.ts:795,817 - Connection handler type mismatch
**Error**: `{ connection: any }` not assignable to `Partial<ConnectionState>`
**Cause**: Destructuring makes 'connection' required but it's optional in Partial
**Fix**: Changed handlers to `(update: Partial<ConnectionState>)`
**Impact**: Proper type safety for connection.update events

### 4. event-buffer.ts:430 - Wrong argument order
**Error**: Object passed as second arg but logger expects (obj, msg) order
**Fix**: Swapped arguments to `logger.debug({ queuedCount }, 'message')`
**Impact**: Matches logger signature from structured-logger.ts

## Root Cause Analysis

All errors stem from incremental changes where:
- Removed metrics support but missed cleanup reference
- Added connection handlers without checking Partial<T> semantics
- Used logger without verifying parameter order

## Testing

Build verification:
```bash
npm run build  # Should now complete successfully
```

These are compilation errors only - no runtime behavior changes.

https://claude.ai/code/session_VMxqX

src/Utils/event-buffer.ts

@@ -427,7 +427,7 @@ export const makeEventBuffer = (
 	if (config.enableMetrics) {
 		import('./prometheus-metrics').then(m => {
 			metricsModule = m
-			logger.debug('📊 Prometheus metrics loaded, flushing buffered metrics', { queuedCount: metricsQueue.length })
+			logger.debug({ queuedCount: metricsQueue.length }, '📊 Prometheus metrics loaded, flushing buffered metrics')
 			// Flush buffered metrics
 			metricsQueue.forEach(fn => fn())
 			metricsQueue = []