Failed requests 5/19 to present

Title: /v1/youtube/channel/videos returns empty videoIds for all channels since ~May 19, 2026

Body: Since approximately May 19, my production app stopped receiving new videos from this endpoint. Every channel I query — including major channels with daily uploads — returns:

{"videoIds":[],"shortIds":[],"liveIds":[]}

Reproduced with these channels (all have many recent uploads):

• 20VC: https://www.youtube.com/@20VC (also tried as channel URL)

• MKBHD: UCBJycsmduvYEL83R_U4JriQ

• BBC News: UC16niRr50-MSBwiO3YDb3RA

Requests return HTTP 200 with no error. The /v1/youtube/transcript endpoint works normally for direct video URLs, so it's specific to channel-videos.

My API key is active and has credits.

Could someone investigate? My production ingest pipeline has been silent for 48+ hours.