fix(db): repair fresh migration chain

docs/verification/mail-001-job-email-hub.md

@@ -1,6 +1,6 @@
 # MAIL-001 consolidated job-email hub
 
-Updated: 2026-08-10
+Updated: 2026-08-15
 
 Status: `IN PROGRESS`. Canonical hub routing, provider-neutral reads, explicit-confirmed send API, persisted reply/new-message UI, interrupted-send recovery, legacy SMTP retirement, send-attempt/draft export coverage, shared application context and tenant-owned draft persistence/API are implemented and locally verified; remaining provider mailbox actions and full account-deletion lifecycle remain.
 
@@ -142,7 +142,7 @@ Status: `IN PROGRESS`. Canonical hub routing, provider-neutral reads, explicit-c
 - The owning job has a cascade relationship; a real-SQLite two-owner test proves User A sees only User A's draft and deleting User A's job removes only that draft while preserving User B's data.
 - The additive migration has explicit SQLite and MariaDB types plus reversible down SQL. EF reports the model current; backend passes 625/625 and both provider scripts generate successfully.
 - No route, UI, provider call, token or content log was added. Export coverage and the complete SEC-009 deletion lifecycle remain prerequisites before private draft content becomes reachable.
-- A disposable full migration-chain SQLite rehearsal is blocked in the older `AddJobEntityAndProspectStages` migration because it references `LastReminderEmailSentAt` before any migration creates it. The failure occurs before `AddEmailDrafts` and remains tracked as JT-019 schema-chain debt.
+- The repaired historical chain now reaches this migration from a blank standalone SQLite database and remains idempotent. A populated older checkpoint also preserves job data through the chain (V-186); production migration remains gated.
 
 ## Implemented readable draft export coverage