feat: add Jest testing framework and implement unit tests for configuration and service logic

tests/setup.ts

@@ -0,0 +1,19 @@
+// Test setup file
+import { config } from '../src/config/config';
+
+// Mock environment variables for testing
+process.env.DISCORD_BOT_TOKEN = 'test-token';
+process.env.UPTIME_KUMA_URL = 'http://localhost:3001';
+process.env.UPTIME_KUMA_USERNAME = 'test-user';
+process.env.UPTIME_KUMA_PASSWORD = 'test-password';
+process.env.HEALTH_PORT = '3000';
+
+// Mock console methods to reduce noise in tests
+global.console = {
+  ...console,
+  log: jest.fn(),
+  debug: jest.fn(),
+  info: jest.fn(),
+  warn: jest.fn(),
+  error: jest.fn(),
+};