feat(web): light the manifesto one line at a time and rewrite the EN/JA/ZH copy

Every reading paragraph owned its own view timeline spanning 80vh to 50vh,
so two or three paragraphs were mid-sweep at once. Each authored line is now
its own block with its own view() timeline anchored to a fixed reading line
(--lit-line 50vh, --lit-band 1vh); the observer fallback samples each line
against the same reading line and resamples on scrollend so a jump that
skips a block still lands it in the right state. Reduced motion now also
resets the lit-read gradient (the two-class rule outranked the media query).

The EN, JA and ZH manifesto strings are rewritten from the Korean intent as a
native writer would say it, keeping the impact words (wisdom, compute,
tokens, compile) and the four chapters; EN scores 0.0 on the prose linter.

Fixes #8369