feat: fix cursor lag, add Blade Runner city map, trim visual noise

[a20r]

Cursor performance fix

The custom cursor lagged badly, worst near the top of the page. Cause: it was positioned with left/top, which are layout properties — every mousemove triggered a reflow, and the hero is animation-heavy, so the main thread couldn't keep up.

• Position via transform: translate3d(...) — compositor-only, no layout/reflow
• Single requestAnimationFrame loop: the ring tracks the pointer 1:1, the trail lerps toward it
• Replaced the expensive body:has(a:hover) selector with a delegated mouseover/mouseout class toggle
• Custom cursor hidden on touch / coarse-pointer devices

Verified: after moving the mouse, #cursor carries translate3d(800px, 500px, 0px) — pure transform, zero layout cost.

Cleanup (less busy)

• Removed the full-screen #flicker overlay — it animated opacity ~10×/sec, a constant full-viewport repaint that also worsened the cursor lag
• Dropped the second hero "boot" line; trimmed hero badges from 6 to 4
• Status bar: 3 items down to 2

City map (the bonus)

New "City Grid" section — a stylized Blade Runner street map rendered in SVG:

• Angled grid district — offset street grid, generated in JS
• Downtown ring road + radial plaza with converging avenues
• Coastal expressway — curving cyan highway with animated traffic dots (SMIL animateMotion)
• Rail line, bay, junction nodes, and a pulsing plaza marker
• HUD corner brackets, a legend, and a Map nav link
• Road-network glow uses a single SVG filter (renders once — no per-frame cost)

Verification

Screenshotted with headless Chromium:

• Mobile (375px): scrollWidth === innerWidth — no horizontal scroll
• Map, hero, and about sections render correctly
• No JS errors (only a sandbox-only CDN cert warning under file://)

Test plan

• Move the cursor around at the top of the page — should track smoothly
• Scroll to the "City Grid" section — map renders, traffic dots move, plaza pulses
• Check the Map nav link scrolls to the section
• Mobile: confirm no horizontal scroll and the map scales down cleanly
• Confirm the page feels less busy without the flicker overlay

https://claude.ai/code/session_01Y8g3FHp9dy1wN86ThR4hYp

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Generated by Claude Code

[github-actions]

Preview: https://a20r.github.io/previews/pr-4/

Commit: 2c2f85d — updates automatically on new pushes.