complete i18n migration to /[locale]/ with EN+ES content

Full rewrite of the docs site under app/[locale]/ with next-intl
in localePrefix:"always" mode. Every page now exists at both
/en/<path> and /es/<path>; the root / shows a meta-refresh + JS
redirect to /<defaultLocale>/ so GitHub Pages serves something
on the apex URL.

Highlights:
- 107 doc pages migrated to file-per-page JSON namespaces under
  messages/en/ and messages/es/. Spanish content is fully
  translated (no copy-of-English placeholders).
- New documentation for the Active Suppressions section in the
  Settings tab and the per-event Dismiss dropdown in the Health
  Monitor modal.
- New screenshots: dismiss-duration-dropdown.png and an updated
  health-suppression-settings.png.
- Pagefind integrated for client-side search; index is built on
  every CI deploy (not committed).
- RSS feeds: per-locale at /<locale>/rss.xml plus root /rss.xml
  for backward compat.
- Removed the dead app/[locale]/guides/[slug]/ route — every
  guide now has its own static page and no markdown source
  remains.
- Fixed orphan link /guides/nvidia -> /guides/nvidia-manual in
  docs/hardware/nvidia-host.
- Removed obsolete components (footer2, calendar, drawer).

Verified locally with `npm ci && npm run build`: 2804 files in
out/, 231 pages indexed by pagefind, root redirect intact, both
locale roots and the new Active Suppressions docs render OK.

web/next.config.mjs

@@ -1,9 +1,14 @@
 import { fileURLToPath } from 'url'
 import { dirname, join } from 'path'
+import createNextIntlPlugin from 'next-intl/plugin'
 
 const __filename = fileURLToPath(import.meta.url)
 const __dirname = dirname(__filename)
 
+// Wires the next-intl request config at ./i18n/request.ts into the
+// Next.js build. Every page rendered under /[locale]/... gets the
+// per-request messages and locale resolution from there.
+const withNextIntl = createNextIntlPlugin('./i18n/request.ts')
 
 /** @type {import('next').NextConfig} */
 const nextConfig = {
@@ -32,4 +37,4 @@ const nextConfig = {
   },
 }
 
-export default nextConfig
+export default withNextIntl(nextConfig)