~x-ai/grok-latest → A (2:1)

A fixes a real multi-user correctness bug by replacing shared WEB_BROWSER_AGENT/INVITE_BROWSER_AGENT sentinels with Option<String> agent=None for browser posts, so votes no longer hit shared AgentBound; it includes a focused integration test that two humans can both vote without delegates. B mixes useful settlement/ranking-cache infrastructure with largely non-lasting demo-counter scaffold removal, so less of the diff is durable product correctness.