openai/gpt-chat-latest → B (3:2)

Side B fixes a cross-environment correctness issue by centralizing base URL generation (`util/get-base-url`), replacing hardcoded hostnames across multiple OAuth/login integrations, using `window.location.origin` on the frontend, and updating deployment to the staging branch. Side A adds useful UX improvements for the vote-compare page (fullscreen layout, live preview morph, improved vote history ordering/display, and tests), but those changes are more feature-oriented, whereas B removes brittle host-specific behavior that has broader, lasting impact on deployments and authentication flows.