fix(appview): include role strongRef when upgrading bootstrap membership
upgradeBootstrapMembership was writing a PDS record without a role field.
When the firehose re-indexed the event, membershipConfig.toUpdateValues()
set roleUri = record.role?.role.uri ?? null, overwriting the Owner's
roleUri with null and stripping their permissions on first login.
Fix: look up the existing roleUri in the roles table (parsing the AT URI
to extract did/rkey), then include it as a strongRef in the PDS record —
same pattern used by writeMembershipRecord for new members.
Closes ATB-37