fix(app): architecture + UI/UX review fixes

Multi-agent arch/UX review pass. Architecture: real HTTP 404 on not-found,
breadcrumb links by slug not lowercased title, CMS pages surface their
plugins, shared status taxonomy (src/lib/statuses.ts) consumed by all three
frontend consumers, data-driven status filter, typed emdash collections
(src/emdash-collections.d.ts), removed unused @astrojs/react + react deps and
dead pnpm block, tsconfig extends Astro strict preset, dev deps pruned from
the runtime image. UI/UX: fixed StatusBadge WCAG-AA contrast, labelled the
search/filter controls, canonical URL + BreadcrumbList JSON-LD + og:type,
human status labels, filtered result count + recoverable empty state,
auto-submit filters, mobile overflow fixes, skip-to-content, :focus-visible.

Commit the npm lockfile so the Dockerfile's `npm ci` path engages.
astro check: 0 errors / 0 warnings / 0 hints.

CLAUDE.md

@@ -90,3 +90,6 @@ cd app && npm run typecheck
 - Don't change branch promotion semantics (fast-forward only across
   `develop` → `staging` → `production`). Mirroring emdash-kotkanagrilli's
   flow is intentional.
+- Don't commit the dev SQLite DB. `data.db` / `data.db-shm` / `data.db-wal`
+  are dev artifacts (gitignored + dockerignored); they must never live in
+  the source tree. Regenerate via `npm run bootstrap` (`emdash init`).