feat(profile): progression read for the progress-to-next-class widget (unblocks ui #84)

[obrien-k]

What

stellar-ui #84 (progress-to-next-class widget) is open, but the api endpoint it was built to consume — GET /profile/me/progression — was retired as orphaned when the progression widget stalled. The widget can't ship without a progression read.

Scope

• Re-expose a member-facing progression read: current rank, next rank per the seeded RankPromotionRule ladder, and the member's gap per criterion (bytes, quality contributions, account age), honoring rankLocked.
• Register it in src/lib/openapi.ts (the previous endpoint's retirement is also why ui feat(scoring): stylesheet-selection CRS scoring (PRD-03 red-green slice) #84's generated types went stale).
• Alternative outcome: if the widget is dropped as product, close stellar-ui feat(scoring): stylesheet-selection CRS scoring (PRD-03 red-green slice) #84 instead — this issue forces that call rather than leaving the pair half-dead.

Design blueprint exists (2026-07-04 parity deep dive, item J3).

Surfaced by the 2026-07-08 parity harvest.

[obrien-k]

Blueprint detail (deep-scrub item J3), as promised in the body:

• GET /api/profile/me/rank-progress in routes/api/profile.ts; module fn in modules/rankProgression.ts reusing the sweep evaluator's inputs.
• Response: {currentRank, nextRank, criteria: [{key, label, current, required, met}]}; nextRank: null at the top of the ladder or when rankLocked.
• UI: RankProgressWidget.tsx on PrivateHomepage + the member's own UserProfile, per-criterion progress bars (stellar-ui feat(scoring): stylesheet-selection CRS scoring (PRD-03 red-green slice) #84).