ERROR cannot deploy application 'barbican': unknown option 'prefer-ipv6'.
Model measured EMPTY afterwards -- juju validated and aborted atomically, so
nothing is half-applied and Steps 1-3.5 remain good.

The dry-run passed and the deploy did not: --dry-run resolves charms and plans
relations but does NOT validate config option names. A green dry-run is not a
gate on option validity.

Measured against charmhub's own config-yaml per pinned channel: 7 of 13 VIP
charms declare prefer-ipv6, 6 do not. barbican never had it at any channel, so
it was not an obsoleted option -- R2's uniform application was never valid.

Not fixed: invariant 9 couples prefer-ipv6 to the v6 VIP legs, so this needs a
GA-R5 ruling, not a mid-deploy edit.

Owned: my first charmhub query used a wrong field and returned a uniform
'no config' across 13 charms -- implausible, which is what caught it.

Capture: docs/audit/stage5-dc0-deploy-attempt1-20260731.txt

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HvCyrwvYTTcDYnRErfMsNf