~x-ai/grok-latest → B (2:5)

B fixes a core multi-user correctness bug: shared WEB_BROWSER_AGENT/INVITE_BROWSER_AGENT caused AgentBound on first browser vote and blocked every later human; PendingSession.agent becomes Option, UI posts pass no delegate, and a two-user vote integration test locks it in. A’s /- external-root fix and GitHub card/resolvers work are real lasting value, but much of the patch is a module move plus richer import UI, which matters less than unblocking multi-user voting.