feat(12.1-02): read-only preview screen with a status hint and record actions

- config_form.yaml preview block (optional headerPartial), reported in the form schema as preview
- fields with context: preview show only on the preview screen and are never written
- form messages preview and edit; recordActions without a preview block stops boot
- SPA route {id}/preview, PreviewView and PreviewField, record actions in the footer
- mapWinterUrl maps preview/:id; the update form returns to the preview
- summer-callout partial style classes for status hints
- README, docs, OpenAPI document, TS types and the embedded build updated

modules/phrasebook/backend/lang/en/lang.yaml

@@ -67,6 +67,7 @@ form:
   update: Edit
   create: Create
   return_to_list: Back to list
+  return_to_preview: Back to preview
   close: Close
   confirm: Confirm
   saving: Saving…
@@ -183,6 +184,8 @@ messages:
     saved: Saved
     delete_confirm: Delete this record?
     deleted: Record deleted
+    preview: Record preview
+    edit: Edit record
   relation:
     link: Add
     link_hint: Choose the records to link.