feat(website): turn blog tags into topic hubs

Tags were decorative: a plain span on every card and post header, with no
page, filter or search behind them, and a vocabulary of 32 slugs across 16
posts where 22 slugs appeared once. They now form a closed vocabulary of ten
topics (src/lib/blog-tags.ts) that the content collection schema enforces, so
an unknown slug fails the build instead of minting a new tag.

Every used tag gets a hub at /blog/tag/<tag>/ with CollectionPage and
BreadcrumbList structured data; the blog index and the hubs show a "Topics"
rail with post counts; and every chip links to its hub. The cards become
<article> elements with the title link stretched over the card, because chip
links cannot nest inside a card that is one big <a>.

Posts are retagged to the new vocabulary. A structural test covers the rail,
each hub, the chip targets, the sitemap and the absence of nested anchors.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

CLAUDE.md

@@ -330,7 +330,7 @@ This is an Nx monorepo with the following structure:
 - **apps/electron-backend-e2e** - Playwright E2E tests against the Electron app
 - **apps/stalker-mock-server** - Mock Stalker/Ministra portal for dev and E2E
 - **apps/xtream-mock-server** - Mock Xtream Codes API for dev and E2E
-- **apps/website** - Astro + Tailwind landing page, blog (guides carry `faq:` frontmatter → FAQPage JSON-LD), per-OS download landing pages (`/download/`, `/download/{windows,macos,linux}/`) plus the Docker page (`/download/docker/`) feature landing pages (`/features/`, registry in `src/lib/features.ts`) and comparison pages (`/compare/`, registry in `src/lib/comparisons.ts`, comparing IPTVnator's own options rather than other products); direct asset links are resolved at build time from the GitHub Releases API with a `package.json` fallback (`src/lib/downloads.ts`, see `apps/website/README.md`)
+- **apps/website** - Astro + Tailwind landing page, blog (guides carry `faq:` frontmatter → FAQPage JSON-LD; tags are a closed vocabulary in `src/lib/blog-tags.ts` enforced by the collection schema, each with a `/blog/tag/<tag>/` hub), per-OS download landing pages (`/download/`, `/download/{windows,macos,linux}/`) plus the Docker page (`/download/docker/`) feature landing pages (`/features/`, registry in `src/lib/features.ts`) and comparison pages (`/compare/`, registry in `src/lib/comparisons.ts`, comparing IPTVnator's own options rather than other products); direct asset links are resolved at build time from the GitHub Releases API with a `package.json` fallback (`src/lib/downloads.ts`, see `apps/website/README.md`)
 - **libs/** - Shared libraries:
     - **epg/data-access** - EPG services, runtime bridge, program normalization
     - **m3u-state** - NgRx state management for M3U playlists