[feat] Comparison #36 backlog — motion polish, 3D track, curated tools

[VforVitorio]

Dev-ready backlog surfaced by the two Fable audits during the #36 Comparison build. All optional — the tab shipped complete without them.

Motion (GSAP / CSS, reduced-motion gated):

• M1 — staged skeleton→ready reveal (banner slide + card glow ignite + track ribbon draw-on via a revealProgress prop on TrackCanvas). Touches page + canvas.
• M5 — finish beat (a ~500ms dominance-ribbon shimmer sweep on finished).
• M6 — seek "comet" (GSAP quickTo the cursor overlays on discrete seeks only, never during rAF playback).
• M7 — segmented-control thumb slide on speed/mode switches.

3D (defense flex, never a parity gate):

• M8 / spec §7 E3 — r3f 3D track: extruded ribbon w/ elevation, emissive dominance, chase-cam, as a lazy-chunked 4th track-mode; 2D canvas stays default + fallback. The seam is clean — useReplayClock.subscribe + frameAt(t) are consumer-agnostic.

Curated tools (Víctor's picks — evaluate per surface):

• Evil Buttons (evilbuttons.com) for the COMPARE / Strategy run CTA — Motion-animated shadcn button, retokenised to bg-accent. Needs the motion dep — pair with M7 so the dep earns its slot.
• Dither Kit (@grimcodes) — a dithered silhouette of the selected GP's track for the Comparison idle EmptyState (fed by circuitDraw outline), + a Home/landing hero texture. Never behind dense data.
• icons0 (icons0.dev) MCP server — wire in the Race-tab sprint for domain glyphs beyond lucide (flags, helmet, compounds). .mcp.json (gitignored), MIT/Apache only.

Known-minor (P3, cosmetic): the delta sign-fill can appear to end a few hundred metres before the line's right edge on some renders — an ECharts area entrance-animation artifact (mitigated animation:false); data/line/tally are correct.