feat(ui): agent-outdated banner on the NAS settings page (capability gate, Part 3)

- networkStoragePageData threads NetAddSupport (yes/no/unknown) via the short-budget
  netAddSupport probe (2 s ctx + cache — a down agent cannot stall the page)
- storage_network.html: support=no replaces the add form with the Hungarian
  alert-warning banner; share list + remove render in every state; yes/unknown
  render the form unchanged; load-time JS guarded for the formless render
- T5 render test (banner/no-form on 'no', form on yes/unknown); red-proof RP5 run
  (conditional dropped → banner assertions fail) and reverted
- template_id_gate + emoji_gate green

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PSK5g6qYLknKj8u3QAFEr6

controller/internal/web/handlers.go

@@ -1048,6 +1048,9 @@ func (s *Server) storagePageData() map[string]interface{} {
 func (s *Server) networkStoragePageData() map[string]interface{} {
 	data := s.settingsBaseData("storage-network", "Hálózati tárhely")
 	data["NetworkStoragePaths"] = s.networkStorageItems(context.Background())
+	// Capability banner: "no" swaps the add form for the agent-outdated notice (yes/unknown render
+	// the form — flaky states belong to the add-time gate). Short-budget probe, cache-backed.
+	data["NetAddSupport"] = s.netAddSupport()
 	return data
 }