boot-anim: matrix-rain BG + 3s→2s runtime (boot into notepat faster)
Two changes to the startup-fade animation (draw_startup_fade):
1. Matrix-rain background. Pseudo-CJK glyphs falling in columns —
started as an homage to the "garbled-character" bug from when the
firmware loaded a chain-loading EFI binary (splash.efi) directly
and displayed its bytes as UTF-16 CJK. User liked the look, so
kept as a proper boot aesthetic. Glyphs are random 7x9 pixel
patterns drawn per-frame with per-column xorshift seeds (no CJK
font needed). Bright white-green leader, fading green trail.
Rain alpha is dimmed in day mode so the title stays legible; more
prominent in dark mode where it gets the full matrix vibe.
2. Cut animation 180f (3s) → 120f (2s). Hold-period to accept keys
dropped 60f (1s) → 40f (667ms). The 3-second hold was branding
padding; the W hint is legible within 400ms. Shaves 1s off every
cold boot without losing the install-during-boot window.
Sub-effects scaled to the new total (subtitle fade 130→80, badges
60→40). Arpeggio boot notes at f=10/20/30/42 stay put — still
within the 2s envelope, no retune needed.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>