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/storage/scan_linux.go

@@ -246,6 +246,9 @@ func ScanDisks(logger *log.Logger, debug bool) (*ScanResult, error) {
 		}
 	}
 
+	if logger != nil {
+		logger.Printf("[INFO] [storage] Scanning disks")
+	}
 	dbg("starting disk scan")
 	scanStart := time.Now()
 
@@ -341,6 +344,9 @@ func ScanDisks(logger *log.Logger, debug bool) (*ScanResult, error) {
 	enrichWithBlkid(result.AvailableDisks, logger, debug)
 	enrichWithBlkid(result.SystemDisks, logger, debug)
 
+	if logger != nil {
+		logger.Printf("[INFO] [storage] Found %d disks", len(result.AvailableDisks)+len(result.SystemDisks))
+	}
 	dbg("disk scan completed in %s", time.Since(scanStart).Round(time.Millisecond))
 
 	return result, nil