v2.2.5 — Fix restreaming mode for Plex DVR

Bug Fixes

• Remove Content-Length: 0 header that caused Plex DVR (and other clients) to treat the buffered/restreamed response as empty, breaking restreaming mode entirely
• Fix content type detection — default application/octet-stream to video/mp2t so Plex correctly identifies MPEG transport streams

Details

Passthrough mode (direct stream URL to client) was unaffected. The issue only manifested in buffering/restreaming mode where xTeVe proxies the stream — both with the built-in streamer and with ffmpeg. The root cause was two Content-Length: 0 headers telling clients the response body was empty, plus incorrect content-type sniffing for transport stream data.