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/utils/__tests__/indicators.test.ts

@@ -0,0 +1,54 @@
+import { describe, it, expect } from "vitest";
+import {
+  calculateSMA,
+  calculateEMA,
+  calculateRSI,
+  calculateMACD,
+} from "../../utils/indicators";
+
+describe("calculateSMA", () => {
+  it("returns 0 when prices length < period", () => {
+    expect(calculateSMA([1, 2], 5)).toBe(0);
+  });
+
+  it("calculates simple moving average correctly", () => {
+    expect(calculateSMA([1, 2, 3, 4, 5], 5)).toBe(3);
+  });
+});
+
+describe("calculateEMA", () => {
+  it("returns 0 when prices length < period", () => {
+    expect(calculateEMA([1, 2], 5)).toBe(0);
+  });
+
+  it("calculates exponential moving average", () => {
+    const prices = [10, 11, 12, 13, 14, 15];
+    const result = calculateEMA(prices, 3);
+    expect(result).toBeCloseTo(14.125, 2);
+  });
+});
+
+describe("calculateRSI", () => {
+  it("returns 0 when prices length < period + 1", () => {
+    expect(calculateRSI([1, 2, 3], 5)).toBe(0);
+  });
+
+  it("calculates relative strength index", () => {
+    const prices = [100, 102, 101, 105, 107, 110, 108, 115, 120, 119, 121];
+    const result = calculateRSI(prices, 5);
+    expect(result).toBeGreaterThan(50);
+    expect(result).toBeLessThan(100);
+  });
+});
+
+describe("calculateMACD", () => {
+  it("returns 0 when prices length < slowPeriod", () => {
+    expect(calculateMACD([1, 2, 3], 12, 26, 9)).toBe(0);
+  });
+
+  it("calculates MACD line", () => {
+    const prices = Array.from({ length: 30 }, (_, i) => 100 + i * 0.5);
+    const result = calculateMACD(prices);
+    expect(result).toBeCloseTo(-0.96, 2);
+  });
+});