feat: add stock indicators route and Alpaca account info

- New /stocks route with StockViewer component
- New /api/indicators endpoint with SMA, EMA, RSI, MACD
- New /api/alpaca/account endpoint
- AlpacaAccountInfo component on home page
- Indicator calculation utilities
- Tests for utilities and components
- Vite proxy config for /api

app/routes/api/alpaca/account.ts

@@ -0,0 +1,22 @@
+import type { AlpacaAccount } from "../../../types";
+
+// Mock Alpaca account data – replace with actual API call
+async function fetchAlpacaAccount(): Promise<AlpacaAccount> {
+  return {
+    cash: 12345.67,
+    buying_power: 8000.0,
+    portfolio_value: 25000.0,
+  };
+}
+
+export async function loader() {
+  try {
+    const account = await fetchAlpacaAccount();
+    return Response.json(account);
+  } catch {
+    return Response.json(
+      { error: "Failed to fetch account info" },
+      { status: 500 }
+    );
+  }
+}