style: format frontend, docs and skills with prettier; add .prettierignore

One-time prettier --write so the new format:check CI gate starts green.
.prettierignore excludes generated (api-client.ts, documentation.json),
vendored (public/cibg-huisstijl), and backend (dotnet format owns it).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

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

@@ -43,6 +43,7 @@ the list-family rationale to document.
 ## Files
 
 Components to mark (closest CIBG concept in parens):
+
 - `skeleton`, `spinner` (Laadindicatie — no vendored class, verified)
 - `upload/` suite (Bestand-upload)
 - `rich-text-editor` (Tekstgebied)
@@ -52,7 +53,7 @@ Components to mark (closest CIBG concept in parens):
 - `debug-state` (devtool, no CIBG concept)
 - `status-badge` (deliberate custom, documented in code), `card` (`.app-card`),
   `placeholder-chip`
-Plus:
+  Plus:
 - Delete `upload-status-banner` + its story; inline alert at its consumer
 - Header comments on `task-list`/`application-list`/`choice-list`
 - New `src/docs/cibg-gaps.mdx` — title `Foundations/CIBG Gap Register`