~anthropic/claude-sonnet-latest → B (6:4)

B fixes a real product bug (per-group rank indexing was leaking a global offset into gradient styling, and vote history slider/ratio polarity) and adds targeted unit tests (rank_row_style_gradients, winner_side, slider mapping, ranking polarity) that lock in the corrected behavior. A only patches test-support mock server code (regex vs string split, response header codes, request body access) which is useful for keeping E2E tests green but has no effect on the shipped product.