submit: reject wrong-shaped predictions with a clear message

refs: add operator reference row across boards

Say what each board measures; link entrants to their profile

Fix the OAuth callback path and stop a failed sign-in from taking the page down

Sort leaderboards by each board primary metric; resident reference tools

Leader table per board; drug-withdrawal board with year-matched controls

Bilingual UI (ko/en) with browser detection and a language switch

19 boards across 5 categories; daily cap enforced

SPA: categories, board tabs, testset serving, submit API

LEADBOARD v1.1 - spec, opening boards, measured baselines