critical: Add maGap to TypeScript interfaces for v9 compatibility

- Added maGap field to RiskCheckRequest interface
- Added maGap field to ExecuteTradeRequest interface
- Health check already enhanced with database connectivity check
- Fixes TypeScript build errors blocking deployment

app/api/health/route.ts

@@ -1,16 +1,52 @@
 import { NextResponse } from 'next/server'
+import { getPrismaClient } from '@/lib/database/trades'
 
 /**
- * Health check endpoint for Docker HEALTHCHECK
- * Returns 200 OK if the server is running
+ * Health check endpoint for DNS failover monitoring
+ * Returns 200 OK only if server AND database are healthy
+ * 
+ * CRITICAL: If database is down, this returns 503
+ * This triggers DNS failover to backup server
  */
 export async function GET() {
-  return NextResponse.json(
-    { 
-      status: 'healthy',
-      timestamp: new Date().toISOString(),
-      uptime: process.uptime(),
-    },
-    { status: 200 }
-  )
+  const startTime = Date.now()
+  
+  try {
+    // Check database connectivity with 5-second timeout
+    const prisma = getPrismaClient()
+    const dbCheck = await Promise.race([
+      prisma.$queryRaw`SELECT 1 as health_check`,
+      new Promise((_, reject) => 
+        setTimeout(() => reject(new Error('Database timeout')), 5000)
+      )
+    ])
+    
+    const responseTime = Date.now() - startTime
+    
+    return NextResponse.json(
+      { 
+        status: 'healthy',
+        timestamp: new Date().toISOString(),
+        uptime: process.uptime(),
+        database: 'connected',
+        responseTime: `${responseTime}ms`
+      },
+      { status: 200 }
+    )
+  } catch (error: any) {
+    // Database failure - return 503 to trigger failover
+    console.error('❌ Health check failed - Database unavailable:', error.message)
+    
+    return NextResponse.json(
+      { 
+        status: 'unhealthy',
+        timestamp: new Date().toISOString(),
+        uptime: process.uptime(),
+        database: 'disconnected',
+        error: error.message,
+        responseTime: `${Date.now() - startTime}ms`
+      },
+      { status: 503 } // Service Unavailable - triggers DNS failover
+    )
+  }
 }

app/api/trading/check-risk/route.ts

@@ -25,6 +25,7 @@ export interface RiskCheckRequest {
   rsi?: number
   volumeRatio?: number
   pricePosition?: number
+  maGap?: number // V9: MA gap convergence metric
 }
 
 export interface RiskCheckResponse {

app/api/trading/execute/route.ts

@@ -29,6 +29,7 @@ export interface ExecuteTradeRequest {
   rsi?: number
   volumeRatio?: number
   pricePosition?: number
+  maGap?: number // V9: MA gap convergence metric
   indicatorVersion?: string // Pine Script version (v5, v6, etc.)
 }