Fix live search IDs and avoid direct-playing addon URLs

[0oAstro]

Summary

Fixes two related live-search/playback failure modes:

• live search could return a synthetic Stremio/Gelato GUID even when the item was already materialized in Jellyfin, so opening /Items/{id} could 404
• Gelato stream media sources were advertised as direct-playable HTTP URLs, which can leak internal addon/debrid proxy URLs to clients and make remote clients time out instead of proxying through Jellyfin

Changes

• Prefer manager.FindExistingItem(baseItem) in SearchActionFilter.ConvertMetasToDtos and return the canonical item DTO when present.
• Resolve user id from action/route arguments in addition to claims/query params so legacy/detail routes can pass through insert/sync filters correctly.
• Include additional detail/playback/video/subtitle action names in insertable route detection.
• Mark Gelato stream media sources as SupportsDirectPlay=false and stub URL paths in DTO/playback responses so clients use Jellyfin as the proxy instead of trying to open addon-internal URLs directly.

Local verification

Verified against a Jellyfin 10.11.x + Gelato 0.26.15.1 install:

• Search matrix reloaded returned canonical Jellyfin item id instead of synthetic id.
• Search timings remained sub-second to ~1.1s for tested queries.
• /Users/{userId}/Items/{canonicalId} returned 200.
• /Items/{canonicalId}/PlaybackInfo?UserId=... returned media source path /stub, Protocol=File, IsRemote=false, SupportsDirectPlay=false, SupportsDirectStream=true.
• /Videos/{canonicalId}/stream.mkv?MediaSourceId={canonicalId}&Static=true returned HTTP 200 and started streaming via Jellyfin.

Closes #168.

[lostb1t]

im hesitant on this. We dont know what clients ise this for. Maybe it will prevent them for direct playing at all wand a build a transcodee url themselves. If we just stub the path it should be enough

[lostb1t]

this is slow. I dont think its necessarily needed if the insert action catches all routes properly