docs(settings): improve Metadata settings docs

docs/using-seerr/settings/metadata.md

@@ -0,0 +1,53 @@
+---
+title: Metadata Providers
+description: Configure the metadata providers Seerr uses for TV and anime.
+sidebar_position: 8
+---
+
+# Metadata Providers
+
+Seerr fetches descriptive metadata (titles, descriptions, posters, release dates,
+external IDs, etc.) from a number of third-party providers. The
+**Settings → Metadata Providers** page lets administrators pick which provider
+is used for each media type.
+
+A **Test** button at the top and bottom of the page exercises every configured
+provider and updates the two status badges (`TheMovieDB`, `TheTVDB`). Each badge shows one of:
+
+- **Operational** — the test request succeeded.
+- **Not tested** — no test has been run yet in this session.
+- **Failed** — the test request errored; a toast describes which provider(s)
+  failed so the issue can be resolved without scrolling back up.
+
+## Metadata Provider Selection
+
+This section controls which provider is used for which media type.
+
+
+### Series Metadata Provider
+
+Choose between **TheMovieDB** and **TheTVDB** as the source of metadata for TV
+series. TheMovieDB is the default and matches the source used for movies, which
+keeps IDs and artwork consistent across the UI. TheTVDB tends to have richer
+episode-level data for long-running shows.
+
+### Anime Metadata Provider
+
+Choose between **TheMovieDB** and **TheTVDB** for anime entries. Many users
+prefer **TheTVDB** here because its anime catalogue is typically more complete
+and uses release-aligned numbering.
+
+Selection changes are persisted with the **Save** button at the bottom of the
+page.
+
+
+## Saving and Testing
+
+The **Save** buttons persist changes to `config/settings.json`. The **Test**
+buttons make one request per provider:
+
+- TMDB / TVDB are tested only when selected as the active provider for one of
+  the media types.
+
+If any test fails, a toast is shown for that provider and its status badge is
+updated; the other providers' results are independent.