feat(api): add Next.js proxy routes for ML inference service

src/app/api/predict/route.ts

@@ -0,0 +1,65 @@
+import { NextRequest, NextResponse } from 'next/server';
+
+const INFERENCE_API_URL = process.env.INFERENCE_API_URL || 'http://localhost:8001';
+const INFERENCE_API_TIMEOUT = parseInt(process.env.INFERENCE_API_TIMEOUT || '30000', 10);
+
+export async function POST(request: NextRequest) {
+  try {
+    const body = await request.json();
+
+    // Forward request to Python inference service
+    const controller = new AbortController();
+    const timeoutId = setTimeout(() => controller.abort(), INFERENCE_API_TIMEOUT);
+
+    try {
+      const response = await fetch(`${INFERENCE_API_URL}/predict`, {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+        },
+        body: JSON.stringify(body),
+        signal: controller.signal,
+      });
+
+      clearTimeout(timeoutId);
+
+      // Forward the response from the inference service
+      const data = await response.json();
+
+      if (!response.ok) {
+        return NextResponse.json(
+          { error: data.detail || 'Prediction failed' },
+          { status: response.status }
+        );
+      }
+
+      return NextResponse.json(data);
+    } catch (fetchError: any) {
+      clearTimeout(timeoutId);
+
+      if (fetchError.name === 'AbortError') {
+        return NextResponse.json(
+          { error: 'Prediction request timed out' },
+          { status: 504 }
+        );
+      }
+
+      throw fetchError;
+    }
+  } catch (error: any) {
+    console.error('Predict proxy error:', error);
+
+    // Check if it's a connection error
+    if (error.cause?.code === 'ECONNREFUSED' || error.message?.includes('fetch failed')) {
+      return NextResponse.json(
+        { error: 'Inference service unavailable' },
+        { status: 503 }
+      );
+    }
+
+    return NextResponse.json(
+      { error: 'Internal server error' },
+      { status: 500 }
+    );
+  }
+}