feat(gateway): verify Kakao account ownership

tools/legacy-db-migration/README.md

@@ -79,6 +79,8 @@ next turn.
 
 Kakao members retain their OAuth ID, email, and OAuth metadata.
 `kakao_verified_at` and `kakao_grace_started_at` are set to the migration time.
+The existing `token_valid_until` is copied to `kakao_talk_verified_until` for
+Kakao rows so a still-current “send to me” proof remains current after cutover.
 Legacy password hashes and salts are retained and upgraded to Argon2id after
 the first successful login when
 `GATEWAY_LEGACY_PASSWORD_GLOBAL_SALT` is configured in gateway-api.

tools/legacy-db-migration/src/gateway.ts

@@ -64,6 +64,10 @@ const mapMember = (row: SourceRow, migratedAt: Date, lastLoginAt: Date | null):
         terms_accepted_at: null,
         privacy_accepted_at: null,
         kakao_verified_at: oauthType === 'KAKAO' ? migratedAt : null,
+        kakao_talk_verified_until:
+            oauthType === 'KAKAO'
+                ? toNullableDate(row.token_valid_until, `member.${memberNo}.token_valid_until`)
+                : null,
         kakao_grace_started_at: migratedAt,
         delete_after: toNullableDate(row.delete_after, `member.${memberNo}.delete_after`),
         created_at: toDate(row.REG_DATE, `member.${memberNo}.REG_DATE`),