feat(fp): WP-13 — CIBG-gap register + hygiene + MDX

Mark every hand-rolled shared/ui surface with a `// CIBG-GAP EXTENSION:`
comment + `cibgGap` story parameter (skeleton, spinner, rich-text-editor,
wizard-shell's error summary, application-link's non-navigating row,
debug-state, status-badge, card, placeholder-chip) so deviations from the
CIBG design system are auditable. Add the register MDX
(Foundations/CIBG Gap Register), cross-linked from ADR-0003. Delete the
near-identity upload-status-banner wrapper; its one consumer now uses
<app-alert> directly (a story added to keep the info-banner state covered).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docs/backlog/WP-13-cibg-gap-register.md

@@ -1,8 +1,20 @@
 # WP-13 — CIBG-gap register + hygiene + MDX
 
-Status: todo
+Status: done (<pending commit>)
 Phase: 2 — CIBG fidelity
 
+> **Deviation:** WP-11/12 ran first but left no markers (deferred to this WP, as their own
+> files note), so this WP defines the marker format fresh per its own Decisions block —
+> not adopted from 11/12. The Decisions block's `task-list → Actieblok` mapping is stale:
+> no `.actieblok`/`actie` class exists in the vendored CSS, and `task-list`'s own header
+> comment already (accurately) documents it as composing `choice-list`'s Keuzelijst
+> pattern rather than a distinct Actieblok one — left as-is rather than forced to claim a
+> nonexistent mapping. `application-link`'s `.static-row` (flagged as a marked-gap
+> candidate in this file's own correction note) got the marker too. The optional
+> `check:cibg-gaps` script (step 4) is skipped: the register is nine rows, reviewed at PR
+> time same as any other doc — a CI script to diff it against code markers is complexity
+> the size of the problem doesn't warrant (noted, not built).
+
 > **Correction (CIBG UI fidelity pass, b5c5d30):** this WP assumed the `upload/` suite
 > had no vendored CIBG classes and would be marked as a CIBG-gap ("Bestand-upload").
 > The vendored build actually ships a full upload vocabulary (`.file-picker-drop-area`,
@@ -72,11 +84,11 @@ Components to mark (closest CIBG concept in parens):
 
 ## Acceptance criteria
 
-- [ ] Every component with hand-rolled surface CSS either wraps vendored classes or
+- [x] Every component with hand-rolled surface CSS either wraps vendored classes or
       carries the marker (spot-check with a grep for `styles: [` vs markers).
-- [ ] Register MDX complete, linked from ADR-0003.
-- [ ] `upload-status-banner` gone; consumer green; no story coverage lost.
-- [ ] List trio documented.
+- [x] Register MDX complete, linked from ADR-0003.
+- [x] `upload-status-banner` gone; consumer green; no story coverage lost.
+- [x] List trio documented.
 
 ## Verification