feat: comprehensive INFO/WARN/ERROR logging across all controller modules

Add structured operational logging at INFO, WARN, and ERROR levels to
every controller module. Standardize custom prefixes ([GEO], [SCHED],
[SYNC]) to use [INFO/WARN/ERROR] [module] format. Fix misleveled logs
(WARN->ERROR for data loss scenarios, WARN->INFO for routine operations).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

controller/internal/cloudflare/zone.go

@@ -52,6 +52,7 @@ func (c *Client) GetZoneID(ctx context.Context, domain string) (string, error) {
 		}
 	}
 
+	c.logger.Printf("[WARN] [cloudflare] No zone found for domain %s", domain)
 	return "", fmt.Errorf("no Cloudflare zone found for domain %q", domain)
 }