feat(deezer): Add artist bio, top tracks, related artists and language support (#4720)

* feat(deezer): add functions to fetch related artists, biographies, and top tracks for an artist

Signed-off-by: Deluan <deluan@navidrome.org>

* feat(deezer): add language support for Deezer API client

Signed-off-by: Deluan <deluan@navidrome.org>

* fix(deezer): Use GraphQL API for translated biographies

The previous implementation scraped the __DZR_APP_STATE__ from HTML,
which only contained English content. The actual biography displayed
on Deezer's website comes from their GraphQL API at pipe.deezer.com,
which properly respects the Accept-Language header and returns
translated content.

This change:
- Switches from HTML scraping to the GraphQL API
- Uses Accept-Language header instead of URL path for language
- Updates tests to match the new implementation
- Removes unused HTML fixture file

Signed-off-by: Deluan <deluan@navidrome.org>

* refactor(deezer): move JWT token handling to a separate file for better organization

Signed-off-by: Deluan <deluan@navidrome.org>

* feat(deezer): enhance JWT token handling with expiration validation

Signed-off-by: Deluan <deluan@navidrome.org>

* refactor(deezer): change log level for unknown agent warnings from Warn to Debug

Signed-off-by: Deluan <deluan@navidrome.org>

* fix(deezer): reduce JWT token expiration buffer from 10 minutes to 1 minute

Signed-off-by: Deluan <deluan@navidrome.org>

---------

Signed-off-by: Deluan <deluan@navidrome.org>

core/agents/deezer/responses.go

@@ -29,3 +29,38 @@ type Error struct {
 		Code    int    `json:"code"`
 	} `json:"error"`
 }
+
+type RelatedArtists struct {
+	Data  []Artist `json:"data"`
+	Total int      `json:"total"`
+}
+
+type TopTracks struct {
+	Data  []Track `json:"data"`
+	Total int     `json:"total"`
+	Next  string  `json:"next"`
+}
+
+type Track struct {
+	ID           int      `json:"id"`
+	Title        string   `json:"title"`
+	Link         string   `json:"link"`
+	Duration     int      `json:"duration"`
+	Rank         int      `json:"rank"`
+	Preview      string   `json:"preview"`
+	Artist       Artist   `json:"artist"`
+	Album        Album    `json:"album"`
+	Contributors []Artist `json:"contributors"`
+}
+
+type Album struct {
+	ID          int    `json:"id"`
+	Title       string `json:"title"`
+	Cover       string `json:"cover"`
+	CoverSmall  string `json:"cover_small"`
+	CoverMedium string `json:"cover_medium"`
+	CoverBig    string `json:"cover_big"`
+	CoverXl     string `json:"cover_xl"`
+	Tracklist   string `json:"tracklist"`
+	Type        string `json:"type"`
+}