feat(i18n): full app + docs localization (de/en)

- translate remaining pages/components (admin, analytics, redundancy,
  trash, compare, browse, watchlist, admin tools tab, category combobox,
  theme toggle, tool preview card, tool-new/edit) to t() calls
- locales: 453 keys each, parity verified
- docs: bilingual handbook + release notes via *.en.md variants,
  language-aware docs.tsx (markdown paths, nav titles, search index),
  LanguageSwitcher in docs header
- generate-docs: emit per-locale handbook/release/search output,
  localized index.json fields (fileEn/titleEn), en-aware snapshots

docs/releases/v0.8.1/handbook/bewerten.en.md

@@ -0,0 +1,39 @@
+
+# Rating
+
+On the detail page of a tool you can share your experience. Click on
+**Submit a rating** (requires an account).
+
+## Form fields
+
+| Field | Required | Notes |
+| --- | --- | --- |
+| **Usefulness** | Yes | 1–5 stars |
+| **Usability** | Yes | 1–5 stars |
+| **Comment** | No | Free text |
+| **Name** | No | Defaults to "Anonymous" |
+
+Next to the fields, the **? icon** links directly to the associated field
+description in the [data model reference](/docs/reference/schemas/ratinginput).
+
+## What happens after submitting?
+
+- Your rating is saved immediately and appears in the **rating list** of the
+  detail page.
+- The **averages** (usefulness, usability, combined) and the **score
+  distribution** are updated.
+- The **statistics** in the [Analytics](/docs/handbook/analytics) section are
+  recalculated.
+
+## Statistic sections on the detail page
+
+- **Rating overview:** usefulness & usability as an average with progress
+  bars.
+- **Score distribution:** number of ratings per star (1★–5★).
+- **History:** line chart of combined/individual values over time
+  (only visible once there are several ratings).
+
+## API
+
+- [`POST /tools/{id}/ratings`](/docs/reference/endpoints/ratings#createRating) — Submit a rating
+- [`GET /tools/{id}/ratings`](/docs/reference/endpoints/ratings#listToolRatings) — Ratings of a tool