#33036 base red: a neutral machine name in the Session status card gallery fixture

The cmux-next checks step "No fleet host names in gallery fixtures" (scripts/cmux-next/check-fixture-host-names.py) is red on feat-cmux-next. It flags webviews/src/agent-session/acpmux/HarnessStatusCard.gallery.tsx:50, a real machine name that #32835 (5e76566b, the Session status card's Host row) put in the sr2 launch fixture. Every PR's cmux-next checks status shows this red.

This replaces it with the neutral my-mac, the same kind of fix as #32764. It's a gallery fixture value only, so the card shows a different host name in the gallery and nothing else changes. No test reads this fixture's machine (HarnessStatusCard.dom.test.tsx has its own).

Base-red-job: cmux-next checks

Checked: python3 scripts/cmux-next/check-fixture-host-names.py gives "Fixture host names: ok (510 fixture files)".

Agent session: agent session

🤖 Generated with Claude Code

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Summary by cubic

Fixes the red cmux-next checks "No fleet host names in gallery fixtures" check by replacing the real machine name cosmic-gray with the neutral my-mac in the Session status card gallery fixture. Only the gallery value changes; no test or behavior is affected.