fix(subtitles): drop symbol-font glyph decoration and recover wide-glyph word gaps

Generated lyric effects can overlay each syllable with animated single letters
rendered through \fn in a symbol font, where ordinary letters draw as sparkles.
Reading them as text corrupted reconstructed lines ("sotto mimi ni ateru to a z
x") and leaked junk cues ("hlk"). A font a style group uses only for scattered
animated single glyphs now marks those events as decoration: they stay out of
fragment reconstruction and are suppressed alongside the line they overlay.

Per-glyph word gaps measured across a wide glyph ("waves|within" over s/w)
normalize to nearly a common advance, so the ratio test missed them. A word
space adds a roughly constant extra distance regardless of neighbor widths, so
glyph runs with enough gap samples also split when the advance exceeds the
width-predicted advance by a material fraction of the line's common unit.
Capital-to-lowercase pairs and short sample counts are excluded; both guards
are pinned by corpus-derived regression tests.

Across the 145-file library corpus this removes every scattered-letter
malformation and recovers 30+ missing word spaces with no other output change.

changes/ass-canonical-animation-lines.md

@@ -1,5 +1,5 @@
 type: fixed
 area: subtitles
 
-- Typeset ASS karaoke and animated signs no longer flood the primary overlay, subtitle sidebar, immersion history, or sentence mining with repeated glyph fragments or full-line color phases. Matching timed comments and full-line boundary events recover the complete authored line without merging ordinary repeated dialogue or separately positioned signs, and dialogue spoken while a song's animation is on screen is kept intact instead of being replaced by the lyric. Entrance and exit frames that run past the authored line timing still resolve to the clean line during lyric transitions, and dialogue spoken while a song's animation is on screen enters immersion and subtitle history without the fragment lines beside it. Dense visual grids (sign walls, countdown frames, scattered glyph typesetting) stay out of the published text, while multi-row CC-style dialogue blocks and wrapped lyric rows are still published.
+- Typeset ASS karaoke and animated signs no longer flood the primary overlay, subtitle sidebar, immersion history, or sentence mining with repeated glyph fragments or full-line color phases. Matching timed comments and full-line boundary events recover the complete authored line without merging ordinary repeated dialogue or separately positioned signs, and dialogue spoken while a song's animation is on screen is kept intact instead of being replaced by the lyric. Entrance and exit frames that run past the authored line timing still resolve to the clean line during lyric transitions, and dialogue spoken while a song's animation is on screen enters immersion and subtitle history without the fragment lines beside it. Dense visual grids (sign walls, countdown frames, scattered glyph typesetting) stay out of the published text, while multi-row CC-style dialogue blocks and wrapped lyric rows are still published. Decorative letters that lyric effects render in symbol fonts over the syllables are dropped with the animation instead of corrupting the reconstructed line or leaking as stray cues.
 - The secondary subtitle overlay drops layered duplicate lines from animated tracks, so a short stack of repeated words collapses to its distinct lines even when the full karaoke heuristic does not apply.

changes/fix-secondary-subtitle-duplication.md

@@ -1,4 +1,4 @@
 type: fixed
 area: overlay
 
-- Secondary subtitles now parse the selected ASS/SRT/VTT source with the primary subtitle deduplication pipeline, preventing layered animation text from appearing several times in the overlay, mined cards, and statistics. Fragmented ASS karaoke keeps spaces authored at event boundaries and recovers Latin word spaces encoded only by positioned fragment gaps. Long ASS lines repeated as dialogue and positioned signs are also collapsed when they differ only in whitespace or terminal punctuation. Dense multi-row sign layouts no longer become concatenated primary or secondary lines. Live mpv text remains the fallback for unreadable tracks and applies full-line duplicate filtering before display.
+- Secondary subtitles now parse the selected ASS/SRT/VTT source with the primary subtitle deduplication pipeline, preventing layered animation text from appearing several times in the overlay, mined cards, and statistics. Fragmented ASS karaoke keeps spaces authored at event boundaries and recovers Latin word spaces encoded only by positioned fragment gaps, including word gaps measured across wide glyphs that width normalization alone reads as ordinary letter advances. Long ASS lines repeated as dialogue and positioned signs are also collapsed when they differ only in whitespace or terminal punctuation. Dense multi-row sign layouts no longer become concatenated primary or secondary lines. Live mpv text remains the fallback for unreadable tracks and applies full-line duplicate filtering before display.