fix(anime): strip disguised HLS segments and report real playback errors

Some hosts prepend a fake image header (a real 1x1 PNG) to every HLS
segment; ffmpeg probes the segment as a picture and mpv drops back to
idle with no window while the browser claims the episode is playing.

- Route bridge-served m3u8 streams through a local strip proxy that
  scans each segment for the first genuine MPEG-TS packet run and drops
  the junk in front of it; playlists get absolute origins rewritten so
  segment requests come back through the proxy. Non-TS bodies pass
  through untouched.
- Only report ok from playEpisode once mpv configures a video output;
  an end-file with reason error surfaces mpv's own message (e.g. "no
  audio or video data played") in the browser status bar instead of
  "Playing". New end-file event plumbed through the mpv IPC client.

docs-site/anime-browser.md

@@ -155,6 +155,21 @@ Selecting an episode resolves the best available stream, applies the source's
 required headers as mpv `http-header-fields`, and loads it. The headers are
 readable back off mpv, so Anki card audio and screenshots fetch correctly too.
 
+HLS streams are routed through a small local proxy before mpv sees them. Some
+hosts disguise their video segments by prepending a fake image header (a real
+1x1 PNG) so scrapers back off; Aniyomi's own player strips this, but ffmpeg
+probes the segment as a picture and playback dies with "no audio or video data
+played". The proxy scans each segment for the first genuine MPEG-TS packet run
+and drops whatever junk sits in front of it. Segments that are not TS (fMP4,
+subtitles, encryption keys) pass through untouched, and direct-file streams
+skip the proxy entirely.
+
+"Playing" in the status bar means playing: after handing mpv the stream,
+SubMiner waits until mpv actually configures a video output before reporting
+success. If mpv gives up instead — a dead host, an undecodable stream — the
+browser shows mpv's error rather than pretending playback started (a failed
+load leaves no mpv window, because the player idles windowless).
+
 ### Japanese audio, and switching tracks
 
 Sources often return a dub and the original audio as two separate entries — or