fix(web): chat and agents show Not running with a Restart action after a hub restart (CL-8507)

[TheGreatAxios]

Summary

• listChatAgents now reports each agent's latestStatus (the newest deployment's status for its asset), alongside the existing liveAddress.
• Chat page (new-chat and thread) and /agents distinguish a terminal deployment (released/failed/destroy_failed/stopped/never deployed) from a starting one (pending/recovering): terminal now shows "Not running" plus a Restart button (useMutation calling redeployRoomAgent, invalidating the chat-agents query and, on the chat page, the thread query too). While restarting, the UI shows "Starting…"; the composer stays disabled until the agent is live.
• agentRosterStatus gains a third state (not-running); the roster's status pill and body copy follow.
• Kept the existing 3s refetch while an agent isn't live, and added the same polling to /agents so a restart or a released→deployed transition shows up without a reload.

Closes CL-8490.

Test plan

• bunx tsc -p apps/web --noEmit
• bun run lint
• bun run fmt
• cd apps/web && bun run build
• cd apps/web && bun test ./src

[linear-code]

CL-8507

CL-8490