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/selfupdate/state.go

@@ -67,5 +67,7 @@ func ClearState(dataDir string, logger *log.Logger) {
 	path := filepath.Join(dataDir, stateFileName)
 	if err := os.Remove(path); err != nil && !os.IsNotExist(err) {
 		logger.Printf("[WARN] Failed to clear update state file: %v", err)
+		return
 	}
+	logger.Printf("[INFO] [selfupdate] Update state cleared")
 }