fix: standardize log prefixes, remove duplicates, add missing module tags

Second-pass logging cleanup: consistent [LEVEL] [module] format across
all 41 files. Remove stale prefixes ([CF], [SYNC], [SCHED], [API],
[STORAGE], [HEALTH], [ROLLBACK]). Remove 5 duplicate log lines. Gate
ungated DEBUG lines. Fix wrong log levels (restore start WARN→INFO).

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

controller/internal/selfupdate/state.go

@@ -66,7 +66,7 @@ func SaveState(dataDir string, state *UpdateState) error {
 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)
+		logger.Printf("[WARN] [selfupdate] Failed to clear update state file: %v", err)
 		return
 	}
 	logger.Printf("[INFO] [selfupdate] Update state cleared")