Why: Running §11 against RDM d63f1db showed three Frontend defects. A
validated template rule with a server blockedReason was disabled for
preview, although the server only restricts formal delivery. A reviewer
opening the document in another session could not find the author's
submission until an export existed. Template-instance blocks without a
title (cover, sign-off table, fields) rendered as blank canvas nodes and
reader headings.
Evidence: npx vitest run (35 files, 363 tests passed); npm run build ok;
node scripts/check-knip.mjs (43 <= 43); browser run under
/tmp/renderer-browser-acceptance/20261016T064052Z (item1 172 nodes,
preview generated with the validated template rule).
Impact: Preview is offered for validated/draft rules while formal submit
stays blocked; the current submission comes from rdm.review.doc.status;
untitled nodes show "<kind>(<templateBlockId>)".
Refs: unified renderer plan Task 13 §11
Co-authored-by: Cursor <cursoragent@cursor.com>