fix: remediate audited defects (resolves #29, #30, #31, #32)

- Fix permanent qBittorrent fallback degradation by resetting fallback flags during group-by polling (resolves #29)
- Fix Ombi webhook key mismatch in status endpoint and test mocks (resolves #30)
- Prevent timingSafeEqual TypeErrors on multi-byte CSRF token length mismatches (resolves #31)
- Eliminate duplicate write stream on server.log by delegating to index.js console override (resolves #32)

tests/integration/ombi.test.js

@@ -72,9 +72,9 @@ const OMBI_WEBHOOK_CONFIG = {
 };
 
 const OMBI_WEBHOOK_METRICS = {
-  eventCount: 10,
+  eventsReceived: 10,
   pollsSkipped: 5,
-  lastEventTimestamp: 1716326400000
+  lastWebhookTimestamp: 1716326400000
 };
 
 // ---------------------------------------------------------------------------