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/web/auth.go

@@ -88,6 +88,7 @@ func (s *Server) RequireAuth(next http.Handler) http.Handler {
 				s.logger.Printf("[DEBUG] [web] auth: rejected %s %s from %s (%s)", r.Method, r.URL.Path, r.RemoteAddr, reason)
 			}
 			if strings.HasPrefix(r.URL.Path, "/api/") {
+				s.logger.Printf("[WARN] [api] Unauthorized request to %s from %s", r.URL.Path, r.RemoteAddr)
 				w.Header().Set("Content-Type", "application/json")
 				w.WriteHeader(http.StatusUnauthorized)
 				fmt.Fprint(w, `{"ok":false,"error":"authentication required"}`)
@@ -203,6 +204,7 @@ func (s *Server) handleLogout(w http.ResponseWriter, r *http.Request) {
 		delete(s.sessions, cookie.Value)
 		s.sessionsMu.Unlock()
 	}
+	s.logger.Printf("[INFO] [web] User logged out from %s", r.RemoteAddr)
 	http.SetCookie(w, &http.Cookie{Name: sessionCookieName, Value: "", Path: "/", MaxAge: -1})
 	http.Redirect(w, r, "/login", http.StatusFound)
 }
@@ -257,6 +259,7 @@ func (s *Server) invalidateAllSessions() {
 	count := len(s.sessions)
 	s.sessions = make(map[string]*session)
 	s.sessionsMu.Unlock()
+	s.logger.Printf("[INFO] [web] All sessions invalidated (cleared %d)", count)
 	if s.isDebug() {
 		s.logger.Printf("[DEBUG] [web] invalidated all sessions (cleared %d)", count)
 	}
@@ -281,6 +284,9 @@ func (s *Server) cleanupSessions() {
 			}
 			remaining := len(s.sessions)
 			s.sessionsMu.Unlock()
+			if expired > 0 {
+				s.logger.Printf("[INFO] [web] Cleaned up %d expired sessions, %d remaining", expired, remaining)
+			}
 			if s.isDebug() && expired > 0 {
 				s.logger.Printf("[DEBUG] [web] session cleanup: expired=%d remaining=%d", expired, remaining)
 			}