openai/gpt-chat-latest → B (10:1)

Side B fixes a substantive authentication/delegate design bug by changing browser sessions from a shared sentinel agent to `None`, updating `PendingSession` and polling types to use `Option<String>`, and removing the browser delegate from UI posts so multiple human users can vote without conflicting `AgentBound` state. It also adds integration tests covering the multi-user voting scenario and browser login behavior, whereas Side A mainly removes UI toggle/labels and changes placeholder text and button wording with little lasting functional impact.