Refactor for TDD workflow with Vitest and ESLint

- Move API keys from hardcoded values to .env via dotenv
- Extract business logic into src/trading.ts with dependency injection
- Add typed AlpacaClient interface, replace `any` on Alpaca class
- Add Vitest test suites for trading logic and Alpaca wrapper (14 tests)
- Set up ESLint with @typescript-eslint for linting
- Fix getAsset to pass symbol string directly to SDK
- Fix typo (alpacha -> alpaca), remove unused ws/node-fetch deps
- Update .gitignore for node_modules and .env

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/trading.test.ts

@@ -0,0 +1,125 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+import { printAsset, accountBalance, waitForNextOpen, runDay } from './trading';
+import type { Alpaca } from './alpaca';
+
+function mockAlpaca(overrides: Partial<Alpaca> = {}): Alpaca {
+    return {
+        getAccount: vi.fn(),
+        getAssets: vi.fn(),
+        getAsset: vi.fn(),
+        getClock: vi.fn(),
+        getLatestQuote: vi.fn(),
+        getLatestTrades: vi.fn(),
+        ...overrides,
+    } as unknown as Alpaca;
+}
+
+beforeEach(() => {
+    vi.useFakeTimers();
+});
+
+afterEach(() => {
+    vi.useRealTimers();
+    vi.restoreAllMocks();
+});
+
+describe('printAsset', () => {
+    beforeEach(() => {
+        vi.spyOn(console, 'log').mockImplementation(() => {});
+    });
+
+    it('logs fractional when asset is fractionable', async () => {
+        const alpaca = mockAlpaca({
+            getAsset: vi.fn().mockResolvedValue({ symbol: 'TQQQ', fractionable: true, status: 'active', asset_class: 'us_equity' }),
+        });
+
+        await printAsset(alpaca, 'TQQQ');
+        expect(console.log).toHaveBeenCalledWith('TQQQ is fractional');
+    });
+
+    it('logs not fractional when asset is not fractionable', async () => {
+        const alpaca = mockAlpaca({
+            getAsset: vi.fn().mockResolvedValue({ symbol: 'BRK.A', fractionable: false, status: 'active', asset_class: 'us_equity' }),
+        });
+
+        await printAsset(alpaca, 'BRK.A');
+        expect(console.log).toHaveBeenCalledWith('BRK.A is not fractional');
+    });
+});
+
+describe('accountBalance', () => {
+    it('returns the cash value from the account', async () => {
+        const alpaca = mockAlpaca({
+            getAccount: vi.fn().mockResolvedValue({ cash: '10000.00' }),
+        });
+
+        const result = await accountBalance(alpaca);
+        expect(result).toBe('10000.00');
+    });
+});
+
+describe('waitForNextOpen', () => {
+    it('calls getClock and waits until next_open', async () => {
+        const futureDate = new Date(Date.now() + 60000).toISOString();
+        const alpaca = mockAlpaca({
+            getClock: vi.fn().mockResolvedValue({ is_open: false, next_open: futureDate, next_close: futureDate }),
+        });
+
+        const promise = waitForNextOpen(alpaca);
+        await vi.advanceTimersByTimeAsync(60000);
+        await promise;
+
+        expect(alpaca.getClock).toHaveBeenCalled();
+    });
+});
+
+describe('runDay', () => {
+    beforeEach(() => {
+        vi.spyOn(console, 'log').mockImplementation(() => {});
+    });
+
+    it('logs up day when second quote ask price is higher', async () => {
+        const alpaca = mockAlpaca({
+            getClock: vi.fn().mockResolvedValue({ is_open: false, next_open: new Date().toISOString(), next_close: new Date().toISOString() }),
+            getLatestQuote: vi.fn()
+                .mockResolvedValueOnce({ ap: 50.00, bp: 49.90 })
+                .mockResolvedValueOnce({ ap: 50.50, bp: 50.40 }),
+        });
+
+        const promise = runDay(alpaca);
+        await vi.advanceTimersByTimeAsync(61000);
+        await promise;
+
+        expect(console.log).toHaveBeenCalledWith('up day: ', expect.any(Date));
+    });
+
+    it('logs down day when second quote ask price is lower', async () => {
+        const alpaca = mockAlpaca({
+            getClock: vi.fn().mockResolvedValue({ is_open: false, next_open: new Date().toISOString(), next_close: new Date().toISOString() }),
+            getLatestQuote: vi.fn()
+                .mockResolvedValueOnce({ ap: 50.00, bp: 49.90 })
+                .mockResolvedValueOnce({ ap: 49.50, bp: 49.40 }),
+        });
+
+        const promise = runDay(alpaca);
+        await vi.advanceTimersByTimeAsync(61000);
+        await promise;
+
+        expect(console.log).toHaveBeenCalledWith('down day', expect.any(Date));
+    });
+
+    it('logs down day when prices are equal', async () => {
+        const alpaca = mockAlpaca({
+            getClock: vi.fn().mockResolvedValue({ is_open: false, next_open: new Date().toISOString(), next_close: new Date().toISOString() }),
+            getLatestQuote: vi.fn()
+                .mockResolvedValueOnce({ ap: 50.00, bp: 49.90 })
+                .mockResolvedValueOnce({ ap: 50.00, bp: 49.90 }),
+        });
+
+        const promise = runDay(alpaca);
+        await vi.advanceTimersByTimeAsync(61000);
+        await promise;
+
+        expect(console.log).toHaveBeenCalledWith('down day', expect.any(Date));
+    });
+});