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/integrations/manager.go

@@ -125,6 +125,7 @@ func (m *Manager) Toggle(ctx context.Context, provider, target string, enable bo
 
 		start := time.Now()
 		if err := handler.Apply(ac); err != nil {
+			m.logger.Printf("[ERROR] [integrations] Integration %s apply failed: %v", key, err)
 			if m.isDebug() {
 				m.logger.Printf("[DEBUG] [integrations] Toggle: Apply failed for %s in %v: %v", key, time.Since(start), err)
 			}
@@ -210,6 +211,7 @@ func (m *Manager) ListForProvider(providerSlug string) []StatusInfo {
 func (m *Manager) buildApplyContext(provider, target string) (*ApplyContext, error) {
 	provStack, ok := m.stacks.GetStack(provider)
 	if !ok {
+		m.logger.Printf("[WARN] [integrations] Failed to build context for %s:%s: provider stack not found", provider, target)
 		return nil, fmt.Errorf("szolgáltató stack %q nem található", provider)
 	}
 
@@ -299,6 +301,7 @@ func (m *Manager) loadDecryptedEnv(s *stacks.Stack) map[string]string {
 	stackDir := filepath.Dir(s.ComposePath)
 	cfg := stacks.LoadAppConfig(stackDir)
 	if cfg == nil {
+		m.logger.Printf("[WARN] [integrations] Failed to load env for %s: app config is nil", s.Name)
 		return nil
 	}
 	if m.encKey != nil {