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

docs/releases/v0.9.0.en.md

@@ -0,0 +1,46 @@
+# v0.9.0 — Release Notes
+
+**Date:** 2026-08-05 · **Tag:** [`v0.9.0`](https://git.kubebase.de/admin/tool-evaluator/releases/tag/v0.9.0)
+
+## New Features
+
+- **Versioning reset:** Documentation starts fresh at `v0.9.0` with this
+  release. Older release notes and version snapshots (v0.6.0–v0.8.6) have been
+  removed. The handbook and reference (API/admin) are now available again for
+  every version — including newer versions.
+- **Language suffixes:** All documentation files now consistently use the
+  `.de.md` and `.en.md` suffixes. This makes it easy to add more languages
+  later; the app automatically serves the matching language variant.
+- **Import — ready-to-use example file:** A ready-to-import YAML example file
+  with 24 common enterprise tools is provided at
+  `docs/examples/import-tools.yaml` (categories such as communication,
+  monitoring, CI/CD, infrastructure). The file is linked from the
+  administration documentation.
+
+## Fixes & Polish
+
+- The version switcher now displays documentation correctly for newer versions
+  as well (previously, missing version snapshots made the handbook and
+  reference unavailable).
+- Wording cleanup: tagline and placeholder texts no longer reference a specific
+  job title ("Rate your Tool.", "Anonymous User"). No gender-specific forms are
+  used anymore.
+
+## API Changes
+
+- No changes compared to v0.8.6 (see `lib/api-spec/openapi.yaml`).
+
+## Operations / Upgrade
+
+- **Migration:** none. Existing tool, rating, and account data remain
+  unchanged.
+- **Breaking Changes:** none.
+
+## Known Limitations
+
+- None within the scope of this release.
+
+## Links
+
+- Commit: [`<short-sha>`](https://git.kubebase.de/admin/tool-evaluator/commit/<short-sha>)
+- Tag: [`v0.9.0`](https://git.kubebase.de/admin/tool-evaluator/releases/tag/v0.9.0)