feat: add stock database with prisma for portfolio persistence

- Initialize Prisma with SQLite and Stock model
- Create database service layer with singleton client
- Add API routes for stock CRUD operations
- Integrate database with analyze page to persist ticker entries
- Add Playwright tests for stock database functionality

app/routes/api/alpaca/positions.ts

@@ -0,0 +1,23 @@
+import Alpaca from "@alpacahq/alpaca-trade-api";
+
+const alpaca = new Alpaca({
+  keyId: process.env.ALPACA_API_KEY!,
+  secretKey: process.env.ALPACA_SECRET_KEY!,
+  baseUrl: process.env.ALPACA_BASE_URL || "https://paper-api.alpaca.markets",
+  retryOnError: false,
+});
+
+export async function loader() {
+  try {
+    const positions = await alpaca.getPositions();
+    return Response.json(
+      positions.map((p: { symbol: string; qty: string; avg_entry_price: string; current_price: string }) => ({
+        ticker: p.symbol,
+        qty: parseFloat(p.qty),
+      }))
+    );
+  } catch (error) {
+    console.error("Alpaca positions error:", error);
+    return Response.json({ error: "Failed to fetch positions" }, { status: 500 });
+  }
+}