fix(subtitles): drop ASS furigana from recorded cues (#233)

docs/architecture/subtitle-overlay-priming.md

@@ -131,7 +131,9 @@ coming and prefetching would otherwise idle for the rest of the cue.
   authored source order when no usable position exists.
 - Half-size kana positioned directly above a same-timed kanji caption is treated as ASS
   furigana. The parser omits it from published cues but retains hidden matching metadata so
-  mpv's raw live text can be reconciled without displaying or mining the reading.
+  mpv's raw live text can be reconciled without displaying or mining the reading. The
+  timing tracker (clipboard copy, recent-line mining) and immersion recorders run the same
+  reconciliation on the `sub-start`/`sub-end` sample, so they record what the overlay shows.
 - Fragment-only ASS karaoke is reconstructed per style before publication. Explicit spaces
   survive concatenation. Latin fragment typesetting with no literal spaces also recovers word
   boundaries represented only by materially larger horizontal `\pos` or `\move` gaps within that