PM-5997: finish September 9 QA and To Do round

[jmgasper]

Summary

• align completed challenge cards with the Figma winner-avatar/medal design and link winners to the Winners tab
• center challenge prize headings and place the mobile timeline before the prize card
• update Marathon Match history layout and request server-authorized member history
• fix Review waitlist wording/eligibility, mobile application rows, and Copilot search compatibility
• fix Gig filter focus, compact policy dialogs, validation copy, and Recruit assignment confirmation
• retain and verify AI workflow scores in My Submissions

Tickets

PM-6160, PM-6190, PM-6250, PM-6258, PM-6268, PM-6271, PM-6272, PM-6273, PM-6274, PM-6275, PM-6276, PM-6277, PM-6278, PM-6279, PM-6280

PM-6095 is intentionally excluded because its remaining Filestack upload failure requires the documented shared firewall allow-list deployment.

API dependencies

• Review API PR TCA-496 - fix for safari double scrollbar #343 must deploy before or with this UI for PM-6278 history privacy and PM-6280 AI score enrichment: PM-6278 PM-6280: protect submission history and expose AI gating scores review-api-v6#343
• Projects API PR PLAT-754 Configurable Tool & Util Routes - master #42 fixes the PM-6279 JSON/JSONB search failure at source; this UI also carries a bounded compatibility path during rollout: Fix PM-6279 copilot opportunity skill search projects-api-v6#42
• Review API PR Gamification Sprint 4 - deploy for QA #341, already merged, is the authoritative waitlist eligibility/persistence contract for PM-6250.

Validation

• 10 changed-area suites, 208 tests passed
• full yarn lint passed
• production build passed with the existing source-map, CSS-order, and bundle-size warnings
• git diff --check passed
• independent review findings for Gig modal sizing, Recruit confirmation, waitlist deployment compatibility, project-name search, and canonical Copilot type facets were addressed