docs(static-pages): backoffice redirect + StaticPages.md

Milestone 7 of the Static Pages Module sprint.

- app.routes.ts: /backoffice/static-pages now redirects to /edit/static-pages
  (absolute redirectTo) instead of rendering BackofficeComingSoonPageComponent
  - Static Pages is a first-class Project Editor module, not a second CRUD
    surface over the same bootstrap.staticPages data.
- New docs/StaticPages.md: full field reference (General/Localization/SEO/
  Media/Publishing), the enabled+status storefront-gating story and its
  backward-compat default (existing/legacy data normalizes to
  enabled+published so nothing gets silently un-published; only new pages
  default to draft), CRUD/search/filter/bulk, the "mutate from the
  unfiltered list" implementation note, rich-text/HTML-mode contract
  (pointer to EDITOR.md), nav integration, and the export/import/draft/
  publish compatibility statement.
- docs/EDITOR.md: Static Pages row in the Sections table (was previously
  absent - the row lived implicitly in Footer's description), HTML editor
  section updated with the Sprint X+2 toolbar additions + validation
  contract, redirect noted near the route line. `docs/Project-Editor.md`
  (named in the original brief) no longer exists - superseded by EDITOR.md
  per that file's own header; documentation went there + the new file
  instead.
- docs/PROJECT.md: doc index entry for StaticPages.md.

Gate: tsc --noEmit, npm test (57/57), arch:check, build all green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/PROJECT.md

@@ -24,6 +24,7 @@ Every tenant conceptually has three surfaces on this one codebase:
 - **[FRONTEND.md](FRONTEND.md)** — app structure, routing, i18n, theming, state management (signals/facades, no NgRx), dynamic rendering.
 - **[BOOTSTRAP.md](BOOTSTRAP.md)** — the `BootstrapConfig` model, field-by-field, with a representative example JSON.
 - **[EDITOR.md](EDITOR.md)** — the Project Editor: every section, the save/publish/draft/reset model, and the field-description/dropdown UX.
+- **[StaticPages.md](StaticPages.md)** — the Static Pages module: full field reference, per-page draft/publish gating, CRUD/search/filter/bulk, rich text, device preview, nav integration (Sprint X+2).
 - **[PROJECT-STRUCTURE.md](PROJECT-STRUCTURE.md)** — folder-by-folder tour of `src/app/**` with a worked "add a new feature" example (admin dashboard).
 - **[ADMIN.md](ADMIN.md)** — Sprint 19 admin dashboard: routing, architecture, data sources, known gaps.
 - `docs/architecture/foundation/**` — the enforced ADRs (ADR-001…ADR-010) and standards docs (Coding-Standards, Naming-Conventions, Dependency-Rules, Folder-Blueprint, Import-Boundary-Matrix, State-Management-Standards, Configuration-Standards, Component-Standards, Service-Standards). These are governance, not narrative — read them directly; `ARCHITECTURE.md` only links to them.