fix(api): add GET /api/charts/[id] and fix batch prediction

- Add GET handler to /api/charts/[id] route to fetch chart metadata
- Fix batch prediction to use regular /predict endpoint with database candles
- Remove /predict/batch usage (was designed for file-based predictions)
- Make volume field optional in CandleData model (database candles don't have volume)
- Convert timestamps to ISO dates for batch requests

Known issue: TA-Lib indicators failing with 'input array type is not double'
- May need to ensure candle data is float64/double type before processing

src/app/api/charts/[id]/route.ts

@@ -3,6 +3,26 @@ import { db } from '@/lib/db';
 import { charts, candles, annotations } from '@/lib/db/schema';
 import { eq } from 'drizzle-orm';
 
+export async function GET(
+  _request: NextRequest,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  const { id } = await params;
+  const chartId = parseInt(id, 10);
+
+  if (isNaN(chartId)) {
+    return NextResponse.json({ error: 'Invalid chart ID' }, { status: 400 });
+  }
+
+  const result = await db.select().from(charts).where(eq(charts.id, chartId)).limit(1);
+  
+  if (result.length === 0) {
+    return NextResponse.json({ error: 'Chart not found' }, { status: 404 });
+  }
+
+  return NextResponse.json(result[0]);
+}
+
 export async function DELETE(
   _request: NextRequest,
   { params }: { params: Promise<{ id: string }> }

src/app/page.tsx

@@ -512,18 +512,12 @@ export default function Home() {
         throw new Error('No candles found for this chart');
       }
 
-      const startTime = candlesData[0].time;
-      const endTime = candlesData[candlesData.length - 1].time;
-
-      // Make batch prediction request
-      const response = await fetch('/api/predict/batch', {
+      // Use regular predict endpoint with all candles from the database
+      const response = await fetch('/api/predict', {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({
-          pair: chartData.name,
-          timeframe: '1h', // TODO: Get from chart metadata
-          start_time: startTime,
-          end_time: endTime,
+          candles: candlesData,
         }),
       });