fix(i18n): a refused node-bound field write has a localized sentence (#5600)

src/MeshWeaver.Documentation/Data/GUI/DataBinding.md

@@ -198,6 +198,7 @@ Mechanics (so you know what's load-bearing):
 - Field-pointer resolution against the node is **case-insensitive**, so a metadata DTO's PascalCase pointer (`Name`, `Description`) and a content editor's camelCase pointer (`harness`, `messageContent`) both bind without the layout area knowing the JSON casing.
 - **Edit-state stays in `/data`.** The click-to-edit toggle (`editState_…`) is transient view state, not node content — it is never written to the node. Only field VALUES are node-bound.
 - A few read-only display controls (the `[Dimension]` / options / formatted-date toggle *labels*) derive their text from the layout-area `/data` stream rather than a value pointer. When you node-bind a toggleable form, keep `/data/{dataId}` as a **one-way live projection** of the node content (`GetMeshNodeStream(path).Select(n => n.Content).Subscribe(c => host.UpdateData(dataId, c))`) so those labels stay correct. This is a pure read mirror — it follows the node, has no save loop, and never writes back, so it is NOT the forbidden replicate-then-save pattern.
+- **🚨 Editability is the PRODUCING AREA's decision, and it is part of the structure.** A node-bound field writes as the viewer, and the owning hub refuses a viewer without `Update` on the node. So the area that emits the control resolves `hub.GetEffectivePermissions(path)` and sets `Readonly = !canUpdate` (or `CanEdit` on the editors that carry it) — never hands a public visitor a box that invites typing its write can only refuse. The course wish books are the reference shape (`AgenticPrimer/WishBook` → `WishBookAreas.Write`, Education#363). **A write that is refused anyway** (grants changed while the page was open, or an area that forgot the check) reaches the view as an `UnauthorizedAccessException`; `BlazorView.UpdatePointer` classifies it as a REFUSAL, not a fault: the person sees the localized `ui.fieldWriteRefused` sentence and the log carries a Warning, instead of the raw English exception in the error modal and an Error line the incident filer turns into a ticket (#5600).
 
 ## Anti-patterns — never do these
 

src/MeshWeaver.Messaging.Hub/Localization/strings.de.json

@@ -806,6 +806,7 @@
   "ui.recycleFailed": "Der Hub unter '{0}' hat nach dem angeforderten Neustart noch nicht wieder geantwortet: {1}",
   "ui.mdFillFieldsGeneratePlan": "*Felder ausfüllen und auf **Plan erzeugen** klicken.*",
   "ui.accessDeniedPlain": "Zugriff verweigert.",
+  "ui.fieldWriteRefused": "Nicht gespeichert: Sie dürfen diese Seite lesen, aber nicht ändern.",
   "ui.accessDeniedAdminsOnly": "Zugriff verweigert — nur für Plattform-Administratoren.",
   "ui.autoSaved": "Änderungen werden automatisch gespeichert",
   "ui.connectRepoFirst": "Zuerst im Tab **GitHub Sync** ein GitHub-Repository verbinden.",

src/MeshWeaver.Messaging.Hub/Localization/strings.en.json

@@ -806,6 +806,7 @@
   "ui.recycleFailed": "The hub at '{0}' has not answered again yet after the recycle was requested: {1}",
   "ui.mdFillFieldsGeneratePlan": "*Fill in the fields and click **Generate plan**.*",
   "ui.accessDeniedPlain": "Access denied.",
+  "ui.fieldWriteRefused": "Not saved: you can read this page, but you may not change it.",
   "ui.accessDeniedAdminsOnly": "Access denied — platform admins only.",
   "ui.autoSaved": "Changes are saved automatically",
   "ui.connectRepoFirst": "Connect a GitHub repository in the **GitHub Sync** tab first.",