Archive SCIM users with in-use profiles instead of 500ing

[SachaProbo]

When a SCIM hard delete targets a profile that is still referenced (e.g. completed document version signatures, FK RESTRICT), profile.Delete fails with 23503 and poisons the surrounding transaction. The existing deactivate fallback then ran on the aborted transaction and failed with 25P02, surfacing to the connector as an opaque 500 and eventually disabling the bridge.

Wrap profile.Delete in a savepoint so the FK violation only rolls back the delete attempt, leaving the outer transaction healthy for the deactivate/archive fallback. Also map FK violations in Membership.Delete to ErrResourceInUse for consistency with MembershipProfile.Delete.

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Summary by cubic

SCIM deletes now archive in-use profiles and return 204 instead of 500. The hard delete runs in a savepoint; on FK violations we fall back to deactivate/archive without aborting the transaction.

Tests +50 -0

• e2e: deleting a SCIM user with a profile referenced by a completed signature returns 204 and marks the profile inactive; test client now records email/password for this flow.

Coredata +6 -0

• Map Postgres 23503/23001 in Membership.Delete to coredata.ErrResourceInUse for consistency with MembershipProfile.Delete.

Service +13 -3

• Wrap profile.Delete in tx.Savepoint; on coredata.ErrResourceInUse fall back to archive/deactivate and return 204.
• Avoids transaction abort on FK RESTRICT so the fallback can proceed.

^{Written for commit f604c48. Summary will update on new commits.}