Fix first-load track selection and media request rendering

[EclipseKnight]

I tracked a few Cavea issues that were all related to first-load behavior and request rendering.

Main problems:

• opening a movie/episode the first time could leave audio/subtitle controls empty until refresh
• preferred language wasn't always used for initial audio/subtitle selection
• "based on previous item" track behavior wasn't being respected in Cavea's initial selection
• requests were fetched but sometimes didn't show in Movie/Series rows
• request posters sometimes didn't render in the requests modal

What I changed:

• Api/StreamController.cs

  • resolve current user from request context and pass that user into GetPlaybackMediaSources
  • retry once when first pass comes back with no track metadata
  • return typed audio/sub entries with selected set
  • pick initial audio/sub based on user language preference with fallback behavior
  • if user has remember track selections enabled, prefer Jellyfin-provided stream indices (AudioStreamIndex / SubtitleStreamIndex and defaults) so previous-item behavior is respected
  • keep HTTP probe fallback if metadata is still empty

• Files/wwwroot/select-to-cards.js

  • added camelCase/PascalCase-safe field reads
  • re-capture item id on SPA navigation before stream fetch
  • keep existing track UI until new data returns (avoids blank first-load controls)
  • retry stream fetch once if first response has no usable tracks
  • respect backend selected flags when building dropdown options

• Files/wwwroot/requests.js

  • normalize status and itemType consistently
  • use tmdbMediaType as fallback for type routing
  • avoid dropping requests because of casing/type mismatch
  • normalize request image values (url(...), quotes, &) and append api_key for same-origin /Items/... poster urls

Manual checks:

• first-open track controls now populate without refresh
• preferred/default track selection behaves correctly on first open
• with remember track selection enabled, next episodes respect previous audio/sub choice
• requests modal now shows pending requests in the correct row
• request posters render correctly

[EclipseKnight]

I pushed one additional fix commit to this same branch:

dc6064a fix(streams): make metadata stream lookup resilient on version switch

Why:
During version switching, Cavea could call api/cavea/metadata/streams with an itemId that didn’t resolve to a real BaseItems.Id, which caused intermittent 404 Item not found and empty audio/subtitle dropdowns.

What changed:

Resolve by itemId first (normal path)
If not found, fallback to mediaSourceId as item id
If still not found, fallback by matching Gelato stream guid from ExternalId on gelato-stream items
Result:
Version switching now consistently returns stream metadata, and track selectors populate correctly instead of failing on first switch.