feat(fx-system): Itim Thai side-bearing fix + prefers-reduced-motion
Phase 6.1: Itim fix — apply letter-spacing: -0.5px + margin-right: -2px
to all <em> in v7-5 sections. Per user memory, Thai display fonts ship
with wide side bearings causing visual gaps after Latin punctuation.
Scope: 20 selectors covering every .fx-* section + .fx-prose (about body).
Phase 6.2: prefers-reduced-motion — kill animations when user prefers.
Disables .fx-marquee-track, .fx-sparkle, .fx-reveal, .fx-stagger animations.
Also hides .fx-hero::after and .fx-faq-a::after decorations.
Phase 6.3: production build verified (22 pages, 0 errors, 1.96s)
Refs: .hermes/plans/2026-06-13_124000-moreminimore-v7-5-migration.md Task 6.1-6.3
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