docs: import TRM design handoff + defer adoption to phase 3.8

A design handoff bundle generated by Claude Design (claude.ai/design)
on 2026-05-02. Defines the Bloomberg/F1-pit-wall aesthetic for TRM:
- ink-on-paper base + race-flag red accent (#E8412B)
- square-edged everything, sharp printed offset shadows
- mono numerics (JetBrains Mono) for any changing value
- Goldplay (real licensed font, three weights in bundle fonts/)
- four surfaces designed: dashboard / leaderboard / mobile / marketing
  (SPA scope is the first two)

The bundle is committed in-tree at TRM_Design_System-handoff/ so 3.8
has the full source material when it picks the work up. Includes:
- Top-level + project READMEs (the design spec)
- chats/chat1.md (intent + iteration history)
- colors_and_type.css (token set, drop-in for Tailwind 4 @theme)
- fonts/ (Goldplay regular/semibold/bold)
- ui_kits/ (HTML prototypes per surface)
- preview/ (per-token visual reference cards)

Updated phase-3-dogfood-readiness/README.md task 3.8 row to point at
the bundle and document the recommended approach (retheme shadcn via
CSS variable overrides + Tailwind 4 @theme, not replace).

Why deferred: foundational tokens are non-blocking for Phase 1 (login
+ placeholder home) and Phase 2 (live map without chrome). Applying
them now would either delay dogfood-blocking work or land partial
styling that gets reworked when 3.8 lands the full pass.

TRM_Design_System-handoff/trm-design-system/project/ui_kits/mobile/README.md

@@ -0,0 +1,13 @@
+# Mobile UI Kit — TRM
+
+Athlete & spectator mobile companion. Inside an iOS frame for context.
+
+## Screens
+- **My race** — athlete view: bib, current split, projected finish, course progress
+- **Following** — spectator view: list of tracked athletes with live status
+
+## Components
+- `BibCard.jsx` — hero bib + projected finish
+- `SplitList.jsx` — vertical timeline of splits
+- `FollowList.jsx` — list of followed athletes
+- `BottomNav.jsx` — tab bar