fix: Improve logging - fix LOG_LEVEL filter, reduce HTTP noise

- Fix LOG_LEVEL filtering logic (was inverted)
- HTTP logs now only show errors (4xx, 5xx) by default
- Add database connection check at startup
- Cron jobs logged on separate lines
- LOG_LEVEL=debug shows all HTTP requests

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

src/config/database.js

@@ -24,5 +24,12 @@ pool.on('error', (err) => {
 // Initialize Drizzle ORM with schema
 export const db = drizzle(pool, { schema });
 
+// Test database connection
+export const testConnection = async () => {
+  const client = await pool.connect();
+  client.release();
+  return true;
+};
+
 // Export pool for direct access if needed
 export { pool };