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/cron/index.js

@@ -6,18 +6,13 @@ import { startAuditCleanupCron, cleanupOldAuditLogs } from './cleanupAuditLogs.j
  * Start all cron jobs
  */
 export const startAllCronJobs = () => {
-  const jobs = [];
-
   // Calendar event notifications
   const calendarJob = startCalendarNotificationCron();
-  jobs.push(calendarJob);
+  logger.info(`Cron: ${calendarJob.name}`);
 
   // Audit logs cleanup
   const auditJob = startAuditCleanupCron();
-  jobs.push(auditJob);
-
-  // Log summary
-  logger.info(`Cron jobs initialized: ${jobs.map(j => j.name).join(', ')}`);
+  logger.info(`Cron: ${auditJob.name}`);
 };
 
 // Export individual functions for testing/manual triggers