docs: cut to v0.9.0 with unified .de/.en naming

- Remove all prior release notes and version snapshots (v0.6.0-v0.8.6)
- Rename handbook to *.de.md; keep *.en.md
- New release notes v0.9.0.de.md/.en.md with v0.9.0 snapshot
- generate-docs.mjs: .de/.en convention incl. search index and en-fallback
- docs.tsx: release fallback now uses version.de.md
- Wording: neutral tagline, anonymous user, no gender forms
- Add docs/examples/import-tools.yaml and link from administration docs

artifacts/toolrate/src/pages/docs.tsx

@@ -740,7 +740,7 @@ function ReleasesView({ versions }: { versions: ReleaseDoc[] }) {
 
 function ReleaseNoteView({ version, doc }: { version: string; doc: ReleaseDoc | null }) {
   const locale = useDocsLocale();
-  const file = doc ? `releases/${localizedFile(doc.file, doc.fileEn, locale)}` : `releases/${version}.md`;
+  const file = doc ? `releases/${localizedFile(doc.file, doc.fileEn, locale)}` : `releases/${version}.de.md`;
   return (
     <div className="flex flex-col lg:flex-row gap-8">
       <div className="flex-1 min-w-0 max-w-3xl">