feat(design): Phase 1 — Editorial-Technical overhaul

feat(design): Phase 1 — Editorial-Technical overhaul

Major visual overhaul of the design system, layout shell, and marketing
landing. Pure CSS/JSX evolution — no class names removed so all 50+ route
view files keep styling. Tests: 1226 pass / 1 unrelated pre-existing fail.

Tokens
- Slate-noir base (#08090f) replaces near-black; more depth, less crush
- Refined violet signature (#8c6dff) — desaturated from candy purple
- New cyan secondary (#36c5d6); amber as warning signal
- Three border weights (subtle / base / strong) used deliberately
- Bigger display type scale (--t-display 72, --t-display-lg 96)
- Sharper geometry: --r-sm 5, --r 7, --r-md 9 (down from 6/8/10)
- Inter Tight + JetBrains Mono with 'calt' 'liga' 'ss01' feature settings
- Three new motion easings (out-expo, out-quart) + --t-slower

Layout shell
- Taller header (60px) with stronger backdrop blur, animated logo
- Search input gets inline magnifier glyph + focus ring
- Nav-user pill gets a green presence dot
- Nav-link active state with gradient underline
- Whole-page atmosphere: subtle dot-grid + dual radial gradients
- Refined pre-launch banner: mono caption + diamond glyph
- Footer rebuilt as 4-col grid (brand+tag, product, platform, legal)
  with bottom strip — replaces single-line link row
- New utilities: .display .eyebrow .section-header .kbd .mono .meta-mono
  .dot-grid .grid-lines .skeleton .stagger .tag .surface-glow
  .divider .divider-vert .btn-secondary .btn-xl .btn-block

Landing rebuild
- New hero: pulsing eyebrow chip, display-scale gradient title,
  two layered radial blobs + masked grid background, refined CTA
  caption with kbd-pill command sequence
- New trust strip (terminology row separating hero from features)
- 6-feature grid (was 3) with refined icons + hover gradient overlay
- New "How it works" 4-step walkthrough with hairline connectors
- Macos-chrome terminal block: dots + title bar + blinking cursor
- New comparison table vs GitHub (10 rows, NEW badge highlights)
- New 3-tier pricing teaser (Free / Pro / Team) with "Most popular" pill
- Closing CTA card with masked dot-grid + gradient bg
- Stagger-in animations driven by .stagger utility
- Full responsive pass at 960 / 640 breakpoints

Backwards compatibility
- All existing CSS class names preserved (verified by class-grep)
- All existing route views render unchanged structurally
- Smoke render: Layout(LandingPage) → 106KB HTML, all sections present