test(mcp): cover startup summary states

[ctharvey]

Part of #196 — MCP cleanup roadmap item 1.

Summary

• add startup-state coverage at the chatCommand() seam
• cover the three startup handoff states the issue thread called out: live bridged, disabled with no live summary, and unbridged startup failure
• preserve configured MCP specs at startup so /mcp can still surface configured-but-unbridged servers on the marketplace fallback path

Why this shape

The issue comment asked for startup summary state coverage before the larger UI/view-model extractions. This keeps the slice narrow and behavior-focused: one small startup handoff fix in chat.tsx, plus focused tests for the state transitions the MCP hub depends on.

Testing

• npm run verify

Refs #196

[esengine]

Verified locally — rebased onto current main and ran the full suite (136 files, 2180 passed). Narrow change to chat.tsx, focused tests for the three startup-handoff states. Thanks!