The check host cannot start a cell: FORGE_REQUIRE_CELLS turned main red (0c82bad5); give the host cells, then require them again #6062

Found 2026-10-26 by the steward: 0c82bad5 (landed 01:54) added FORGE_REQUIRE_CELLS=1 to both check.fast and check.run in forge.json. The check host cannot start a cell, so test/spawn-cell.test.ts "the host holds cells > cells are available" failed on every main check after it. Main was red from 01:54, and 0.7.257 was HELD. The steward removed the variable (b896efa) so main is green again; the cell tests skip on that host as before.

Done when:

• The check host can start a cell (whatever cellsAvailable() needs: user namespaces, cgroup delegation and the limits from #6019), proven by a check run where "a real cell" tests run, not skip.
• Then put FORGE_REQUIRE_CELLS=1 back, so a host that loses cells fails loudly.
• Guard against a repeat: a pull that changes forge.json check commands must pass a full run on the check host before it lands. Its own fast-tier check did not exercise this. Part of #5994.

Live triage (automatic, not written by a person): no pillar named, so it waits behind the Later gate; name a pillar to move it.