feat: project scaffolding and env config loader

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

test/config.test.js

@@ -0,0 +1,57 @@
+import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import { loadConfig } from '../src/config.js';
+
+const REQUIRED_VARS = ['STORAGE_DIR', 'DB_HOST', 'DB_USER', 'DB_PASSWORD', 'DB_NAME'];
+let savedEnv;
+
+beforeEach(() => {
+  savedEnv = { ...process.env };
+});
+
+afterEach(() => {
+  process.env = savedEnv;
+});
+
+describe('loadConfig', () => {
+  it('returns parsed config when all required vars are set', () => {
+    process.env.STORAGE_DIR = './storage';
+    process.env.DB_HOST = 'localhost';
+    process.env.DB_USER = 'user';
+    process.env.DB_PASSWORD = 'pass';
+    process.env.DB_NAME = 'db';
+    process.env.PORT = '4000';
+    process.env.MAX_FILE_SIZE_MB = '50';
+
+    const config = loadConfig();
+
+    expect(config.port).toBe(4000);
+    expect(config.storageDir).toBe('./storage');
+    expect(config.db).toEqual({ host: 'localhost', user: 'user', password: 'pass', database: 'db' });
+    expect(config.maxFileSizeMb).toBe(50);
+  });
+
+  it('applies defaults for optional vars', () => {
+    process.env.STORAGE_DIR = './storage';
+    process.env.DB_HOST = 'localhost';
+    process.env.DB_USER = 'user';
+    process.env.DB_PASSWORD = 'pass';
+    process.env.DB_NAME = 'db';
+    delete process.env.PORT;
+    delete process.env.MAX_FILE_SIZE_MB;
+    delete process.env.RETENTION_HOURS;
+    delete process.env.WORKER_CONCURRENCY;
+
+    const config = loadConfig();
+
+    expect(config.port).toBe(3000);
+    expect(config.maxFileSizeMb).toBe(100);
+    expect(config.retentionHours).toBe(1);
+    expect(config.workerConcurrency).toBe(3);
+  });
+
+  it('throws listing every missing required variable', () => {
+    for (const key of REQUIRED_VARS) delete process.env[key];
+
+    expect(() => loadConfig()).toThrowError(/STORAGE_DIR.*DB_HOST.*DB_USER.*DB_PASSWORD.*DB_NAME/s);
+  });
+});