On a connection failure the user was left without an obvious way to see
why. Open the monitoring column automatically on the transition into the
`error` status (mirroring the connect-success behavior from #1616) so the
diagnostics surface right when they're needed.
- Broaden the auto-open effect to fire on the transition into `error` as
well as `connected`, tracked via a general previous-status ref so it
fires once per transition and never on a mount that starts errored.
- A failed connect never negotiated capabilities, so the failure column
offers History (the local client-side message log) and — for non-stdio
transports — Network (HTTP requests), the entries that explain the
failure. Logs is omitted (it needs the server `logging` capability).
- `effectivePinned` now allows the column while `error`, not only while
`connected`; it still closes on a clean disconnect or narrowing.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BrihGWcrM9JGRyu41nzZYw
85153c6232