v1.2.7 — Capture mpv stderr + stream compatibility flags

What was broken

Users got mpv exited with code 2 with no explanation. SNI was throwing away mpv's stderr output (stderr=subprocess.DEVNULL), so when mpv failed the user couldn't see the actual error reason.

What's fixed

1. Capture mpv stderr

Player now pipes mpv's stdout+stderr instead of DEVNULL. When mpv fails, the error message includes the last 20 lines of mpv output so you can see WHY it failed (expired URL, format error, network issue, etc.).

2. Stream compatibility flags

Added common AllAnime playback fixes:

• --ytdl=no — don't invoke yt-dlp for direct stream URLs
• --force-seekable=yes — allow seeking on non-seekable streams
• --demuxer-lavf-o=fflags=+seekable — lavf seekable flag
• --stream-buffer-size=4096 — larger read buffer

3. Debug mode

sni --debug play "X" now shows mpv's full verbose output live in the terminal (--msg-level=all=v + --terminal=yes). The --debug flag is wired from CLI → Player constructor.

4. Better error message

When mpv fails, the StreamError now includes:

• mpv's actual output (last 20 lines)
• Common fixes list (expired URL, try --debug, different episode, etc.)
• Instead of just mpv exited with code 2

Install

pip install --upgrade sni-cli
sni play "one piece"

If playback still fails, run with debug to see full mpv output:

sni --debug play "one piece"

Verified

• ruff check sni/ → All checks passed
• pytest -q → 44 passed (3.32s)
• Live end-to-end: search → episodes → stream URL resolved
• python -m build → sdist + wheel both pass twine check

Full changelog: v1.2.6...v1.2.7