Scaffold project and implement config, DB schema/queries

- Set up package.json (ESM, scripts), tsconfig.json, vitest.config.ts
- Install runtime and dev dependencies
- Add CLAUDE.md with architecture notes and code quality rules
- Config module with env var parsing and JWT_SECRET validation
- DB schema: users + files tables with FK cascade
- DB queries: createUser, getUserBy*, createFile, getFileById, getFilesByUserId, deleteFile
- Tests for config, db/users, db/files (15 tests passing)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/unit/auth-service.test.ts

@@ -0,0 +1,21 @@
+import { describe, it, expect } from 'vitest';
+import { hashPassword, verifyPassword } from '../../src/services/auth.ts';
+
+describe('services/auth - password hashing', () => {
+  it('hashes a password and verifies it', async () => {
+    const hash = await hashPassword('mysecret');
+    expect(hash).not.toBe('mysecret');
+    await expect(verifyPassword('mysecret', hash)).resolves.toBe(true);
+  });
+
+  it('rejects wrong password', async () => {
+    const hash = await hashPassword('mysecret');
+    await expect(verifyPassword('wrong', hash)).resolves.toBe(false);
+  });
+
+  it('produces different hashes for same password', async () => {
+    const h1 = await hashPassword('same');
+    const h2 = await hashPassword('same');
+    expect(h1).not.toBe(h2);
+  });
+});