docs: replace SHOWCASE-ROADMAP.md with docs/backlog/ (17 WPs)

Turns the prior roadmap sketch into ordered, gated work packages (enforcement
gates, FP/DDD consistency, CIBG fidelity, Storybook curriculum, a11y) from the
2026-07-02 showcase-hardening audit.

docs/backlog/WP-10-button-fidelity.md

@@ -0,0 +1,64 @@
+# WP-10 — CIBG button fidelity
+
+Status: todo
+Phase: 2 — CIBG fidelity
+
+## Why
+
+The vendored CIBG build ships `.btn-primary / .btn-secondary / .btn-danger / .btn-ghost /
+.btn-link / .btn-link--underline / .btn-inline` — and **no** `.btn-outline-primary`,
+`.btn-outline-secondary`, or `.btn-sm` (verified absent from
+`public/cibg-huisstijl/css/huisstijl.min.css`). Three components emit those dead classes
+and render as unstyled Bootstrap defaults instead of CIBG buttons.
+
+## Read first
+
+- https://designsystem.cibg.nl/componenten/knoppen/ (or grep the vendored CSS)
+- `src/app/shared/ui/button/button.component.ts` (~line 14)
+- `src/app/shared/ui/upload/file-input/file-input.component.ts` (~line 38)
+- `src/app/shared/ui/rich-text-editor/rich-text-editor.component.ts` (toolbar, ~lines 55-60)
+
+## Decisions (pre-made, don't relitigate)
+
+- `variant='secondary'` → `.btn-secondary` (CIBG's documented secondary).
+- RTE toolbar buttons → `.btn-ghost`; drop `.btn-sm` — if the toolbar needs a smaller
+  size, that's token-bridge CSS carrying the CIBG-gap marker (format per WP-13; define it
+  inline if WP-13 hasn't run).
+- Add `'ghost'` to the atom's variant union (CIBG documents it; the RTE needs it).
+- Icon affordances (chevron/pijl): implement **only if** icon classes exist in the
+  vendored CSS — inspect first; otherwise record as a gap in the WP-13 register and skip.
+
+## Files
+
+- `src/app/shared/ui/button/button.component.ts` + `button.stories.ts`
+- `src/app/shared/ui/upload/file-input/file-input.component.ts`
+- `src/app/shared/ui/rich-text-editor/rich-text-editor.component.ts`
+- Any story/snapshot referencing the old classes
+
+## Steps
+
+1. Fix the variant map in the button atom; add `ghost`.
+2. file-input label-button → `btn btn-secondary`.
+3. RTE toolbar → `btn btn-ghost` (+ marked size CSS if needed).
+4. Grep-check `btn-outline`/`btn-sm` gone repo-wide.
+5. Storybook visual review of Button (all variants), FileInput, RichTextEditor against
+   designsystem.cibg.nl/componenten/knoppen.
+
+## Acceptance criteria
+
+- [ ] `grep -rn "btn-outline\|btn-sm" src/app` → empty.
+- [ ] Button story shows all CIBG variants incl. ghost; visuals match the design system.
+- [ ] Axe still green (contrast can change with real button styles).
+
+## Verification
+
+GREEN + `npm run test-storybook:ci`. Manual Storybook review of the three components.
+
+## Out of scope
+
+Other invented classes (WP-11); datablock (WP-12).
+
+## Risks
+
+Visual regressions where outline-secondary "worked by accident" via Bootstrap base rules
+— the story review step is the catch.