docs: project docs, scripts, deployment configs, and evidence

docs/evidence/ops/2026-03-28/quality/COVERAGE_REMEDIATION_20260328-140215.md

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+# 2026-03-28 Q-004 Coverage Remediation Pass 21
+
+## Scope
+
+- Continue strict `Q-004` closure work after Pass 20.
+- Fully close the shared error-model hotspot in:
+  - `frontend/admin/src/lib/errors/AppError.ts`
+  - `frontend/admin/src/lib/errors/index.ts`
+- Re-verify closure through targeted error-module tests and full frontend validation.
+
+## Changes
+
+### Frontend
+
+- Added dedicated error-module coverage in:
+  - `frontend/admin/src/lib/errors/AppError.test.ts`
+- Newly covered behavior includes:
+  - `AppError` constructor defaults
+  - explicit option handling with `cause`
+  - backend response to error-type mapping
+  - factory helpers for auth / forbidden / validation / network errors
+  - `isAuthError`, `isForbidden`, and `isNetworkError`
+  - user-facing message mapping across all error types
+  - `isAppError`
+  - `getErrorMessage`
+  - `isFormValidationError`
+
+### Backend
+
+- No backend code changes were required in this pass.
+
+## Verified Commands
+
+```powershell
+cd D:\project\frontend\admin
+npm.cmd run test:run -- src/lib/errors/AppError.test.ts
+npm.cmd run lint
+npm.cmd run build
+npm.cmd run test:coverage
+```
+
+## Results
+
+### Frontend coverage
+
+- Overall:
+  - statements `93.07%`
+  - branches `81.35%`
+  - functions `90.32%`
+  - lines `93.26%`
+- Target areas:
+  - `src/lib/errors/AppError.ts`: statements `100%`, branches `100%`, functions `100%`, lines `100%`
+  - `src/lib/errors/index.ts`: statements `100%`, branches `100%`, functions `100%`, lines `100%`
+
+### Validation outcomes
+
+- Full frontend coverage run now completes with:
+  - `51` passing test files
+  - `238` passing tests
+- The required sequential frontend validation path passed:
+  - `test:run -- src/lib/errors/AppError.test.ts`
+  - `lint`
+  - `build`
+  - `test:coverage`
+
+## Validation Notes
+
+- The successful frontend coverage run still emits one post-summary jsdom `AggregateError` network-noise line.
+  - It does not fail the command.
+  - It remains a real validation-hygiene issue and cannot be hidden.
+
+## Real Conclusion
+
+- `src/lib/errors/AppError.ts` is no longer an open `Q-004` gap.
+- `src/lib/errors/index.ts` is no longer an open `Q-004` gap.
+- `Q-004` still cannot be honestly declared closed.
+- After this pass, the remaining higher-value frontend gaps narrow further to:
+  - `src/pages/admin/ImportExportPage/ImportExportPage.tsx`
+  - `src/pages/NotFoundPage/NotFoundPage.tsx`
+  - `src/lib/hooks/useBreadcrumbs.ts`
+  - `src/app/providers/ThemeProvider.tsx`
+  - the post-summary jsdom `AggregateError` coverage-noise hygiene issue