Re-review follow-up (#1622):
- Observation A: a returning user whose last-pinned monitor tab was
History would land on the (empty) History tab on a stdio failure instead
of the Console diagnostic. Root cause: History is *always* empty on a
connect failure (the message log clears on the error transition), yet it
was pushed unconditionally, so it could precede/hide the real diagnostic.
Fix: content-gate History like Console/Network — only offer it when it
has entries. On a fresh failure the diagnostic (Console/Network) is the
only tab, so it always leads, without touching tab-switching or adding
state. This also resolves the earlier "opens onto an empty column" note:
when nothing has been captured yet, monitorAvailable is empty and the
column stays closed, opening reactively once stderr/fetch content lands.
Tests: stdio/HTTP failure now assert the diagnostic leads and History is
absent; added "leads with Console even when stored tab was History",
"keeps the column closed until a diagnostic has content", and "offers
History when it has captured content". Verified live (time server →
Console-only column). Full `npm run ci` passes.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BrihGWcrM9JGRyu41nzZYw
a759777ceb