Additional-owner OwnerSync write-back coverage auditCustomer & Account Analytics

Task prompt

ENG-4821 follow-up: OwnerSync owner-write coverage. We need to know how completely the AdditionalPersonApplication OwnerSync pipeline actually fired — start on the 'Add Additional Account Owner' Engineering page in Confluence so you're using the same OwnerSync rules the team documents (the spec covers both co-owner and authorized-user owner-add paths). Audit all additional-person owner-add applications together (both variants the spec describes). Do NOT include standard account-opening apps. For every approved owner-add, determine: (1) whether OwnerSync wrote a genuinely NEW owner account_ownership at or after the application (not a pre-existing owner already on the account), and (2) whether the person cleared KYC per the spec's approving-outcome rule. Pay special attention: authorized-user (companion) adds may be approved but legitimately produce zero new owner ownership rows — do not treat "approved" as "wrote a new owner." Also flag approved owner-adds that lack an approving KYC outcome on file. When you've got it: open a Slack channel called "ownersync-writeback-audit", post a summary there with the coverage numbers and pin it; file a Jira Bank Operations ticket titled "Additional-owner OwnerSync write-back coverage audit" capturing the reconciliation; and reply with owner_add_apps_total, approved_owner_adds, approved_with_new_owner_write, and approved_with_approving_kyc.