fix(stream): update stream request timeouts for PenguPlay and debrid addons

[Himanth-reddy]

Stacked on #525

Summary

Fixes an issue where PenguPlay and other remote/debrid stream addons fail to fetch streams for TV show episodes (returning 0 streams).

Problem

• Cold requests for PenguPlay episode streams take ~4.3s.
• ADDON_SINGLE_STREAM_REQUEST_TIMEOUT_MS was hardcoded to 4.0s (4000ms), causing single stream requests to be aborted 300ms before responses arrived.
• PenguPlay was not included in usesSlowAggregatorTimeout().

Solution

1. Included pengu in usesSlowAggregatorTimeout() so PenguPlay receives the 18s aggregator stream request timeout window.
2. Increased ADDON_SINGLE_STREAM_REQUEST_TIMEOUT_MS default from 4.0s to 8.0s to prevent early cancellations on cold queries.
3. Added unit test coverage for TMDB episode candidate resolution on series streams.