docs(skills): extract house recipes as Claude Code skills for SSP templating

8 template-generic skills in .claude/skills/ (new-feature, new-context,
value-object, form-machine, bff-endpoint, mutation-command, ui-component,
new-ssp), condensed from CLAUDE.md/ARCHITECTURE/fp-tea/ADRs and pointing at
this repo's worked examples. CLAUDE.md gains a pointer.

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

.claude/skills/bff-endpoint/SKILL.md

@@ -0,0 +1,57 @@
+---
+name: bff-endpoint
+description: Add a screen-shaped read — backend endpoint returning a decision-enriched DTO, regenerated typed client, contracts DTO, adapter with parse boundary, application store, <app-async> in the page. Use for any new data a page needs.
+---
+
+# BFF-lite read endpoint (decision DTO)
+
+One screen = one endpoint returning everything that screen needs, **decisions
+included**. The FE renders the server's decisions; it never recomputes business
+rules (ADR-0001). Per rule choose: **decision flag** (server computes the boolean)
+or **config value** (server sends the threshold, FE applies it for instant feedback,
+server re-validates as authority).
+
+## Steps
+
+1. **Backend** (`backend/src/BigRegister.Api/`): minimal-API endpoint under `/api/v1`,
+   wire DTO in `Contracts/`, rule in `Domain/` with a test in
+   `backend/tests/BigRegister.Tests/`. Rejections are ProblemDetails (RFC 7807, 422).
+2. **Regenerate the client**: `npm run gen:api` — commits `backend/swagger.json` +
+   `src/app/shared/infrastructure/api-client.ts` (CI has a drift check; never edit the generated file).
+3. **DTO** in `<context>/contracts/<name>.dto.ts` — plain interfaces/string-literal
+   unions. Contracts import **nothing** (lint-enforced): no Angular, no aliases, no relative imports.
+4. **Adapter** in `<context>/infrastructure/<name>.adapter.ts` — the only place HTTP lives:
+
+   ```ts
+   @Injectable({ providedIn: 'root' })
+   export class DashboardViewAdapter {
+     private client = inject(ApiClient);
+     viewResource() { return resource({ loader: () => this.client.dashboardView() }); }
+   }
+   // The trust boundary: validate the untrusted shape AND map DTO → domain.
+   export function parseDashboardView(json: unknown): Result<string, DashboardView> { … }
+   ```
+
+   The mapping may read as an identity copy today — the point is the **types** differ,
+   so the compiler forces a real mapping the moment the wire diverges.
+5. **Application store** exposes the resource as `RemoteData` (`fromResource`,
+   combine sources with `map`/`map2`/`andThen` from `@shared/application/remote-data`).
+   UI never imports infrastructure (lint-enforced).
+6. **Page** renders through `<app-async>` (`shared/ui/async`) — one of
+   loading/empty/error/loaded by construction. Check all four states with the
+   dev-only `?scenario=slow|loading|empty|error` toggle.
+
+## Worked example (trace one name through all layers)
+
+`dashboard-view`: `backend/src/BigRegister.Api` endpoint →
+`src/app/registratie/contracts/dashboard-view.dto.ts` →
+`src/app/registratie/infrastructure/dashboard-view.adapter.ts` (+ spec on `parseDashboardView`) →
+`src/app/registratie/application/big-profile.store.ts` → dashboard page.
+
+## Verify
+
+```bash
+cd backend && dotnet test && cd ..
+npm run gen:api && git diff --exit-code src/app/shared/infrastructure/api-client.ts
+npm test && npm run lint && npm run build
+```