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/components/ui/mermaid.tsx

@@ -0,0 +1,82 @@
+"use client"
+
+import { useEffect, useRef, useState } from "react"
+import { cn } from "@/lib/utils"
+
+interface MermaidProps {
+  chart: string
+  className?: string
+}
+
+export function Mermaid({ chart, className }: MermaidProps) {
+  const containerRef = useRef<HTMLDivElement>(null)
+  const [error, setError] = useState<string | null>(null)
+  const [rendered, setRendered] = useState(false)
+
+  useEffect(() => {
+    let cancelled = false
+
+    async function render() {
+      try {
+        const mermaid = (await import("mermaid")).default
+        mermaid.initialize({
+          startOnLoad: false,
+          theme: "default",
+          securityLevel: "strict",
+          fontFamily:
+            'ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif',
+          flowchart: {
+            htmlLabels: true,
+            curve: "basis",
+            useMaxWidth: true,
+          },
+        })
+
+        const id = `mmd-${Math.random().toString(36).slice(2, 10)}`
+        const { svg } = await mermaid.render(id, chart)
+
+        if (!cancelled && containerRef.current) {
+          containerRef.current.innerHTML = svg
+          setRendered(true)
+        }
+      } catch (err) {
+        if (!cancelled) {
+          setError(err instanceof Error ? err.message : "Failed to render diagram")
+        }
+      }
+    }
+
+    render()
+
+    return () => {
+      cancelled = true
+    }
+  }, [chart])
+
+  if (error) {
+    return (
+      <div
+        className={cn(
+          "my-6 rounded-md border border-red-200 bg-red-50 p-4 text-sm text-red-800",
+          className,
+        )}
+      >
+        <p className="font-medium mb-1">Diagram failed to render</p>
+        <pre className="text-xs whitespace-pre-wrap">{error}</pre>
+      </div>
+    )
+  }
+
+  return (
+    <div
+      className={cn(
+        "my-6 overflow-x-auto rounded-md border border-gray-200 bg-white p-4",
+        !rendered && "min-h-[120px] flex items-center justify-center text-sm text-gray-500",
+        className,
+      )}
+    >
+      {!rendered && <span>Loading diagram…</span>}
+      <div ref={containerRef} className="flex justify-center [&_svg]:max-w-full [&_svg]:h-auto" />
+    </div>
+  )
+}