- drop the duplicate parseText full parse per line; the termsFind scanner walk
is now authoritative and emits its own unparsed filler runs (parseText kept
only as error fallback)
- install scan helpers once per parser window (__subminerYomitanScan) instead
of re-shipping ~500 lines of script per subtitle line
- persist termsFind results across lines in a window-scoped LRU keyed by
substring, invalidated via a cache epoch on dictionary/settings changes
- skip lookups at punctuation/whitespace positions and cap the shrinking-window
retry ladder at 4 lookups per position
- build tokenizer runtime deps once (JLPT lookup cache never hit before; mecab
availability check ran per line)
- stop restarting the prefetch run on every subtitle change; resume prefetch
only after the tokenized payload lands, not on provisional raw emits
- add per-stage debug timings (scanMs/mecabMs/frequencyMs/annotateMs)
