feat(tenant): dedup article publish status by latest record per target

Aggregate publish status from the latest record per publishing target
using a shared target-identity expression, so retries and multi-record
targets no longer inflate the status buckets.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

server/internal/tenant/app/article_service.go

@@ -110,24 +110,18 @@ const articlePublishStatusAggregateJoin = `
 			       BOOL_OR(latest.status_bucket = 'success') AS has_success,
 			       BOOL_OR(latest.status_bucket = 'failed') AS has_failed
 			FROM (
-				SELECT DISTINCT ON (
-					COALESCE(pr.target_type, 'platform_account'),
-					COALESCE(pr.platform_account_id, pr.target_connection_id)
-				)
+				SELECT DISTINCT ON (` + publishRecordTargetIdentityExprSQL + `)
 				       CASE
 				           WHEN pr.status IN ('success', 'published', 'publish_success') THEN 'success'
 				           WHEN pr.status IN ('publishing', 'pending', 'queued', 'running') THEN 'publishing'
 				           ELSE 'failed'
 				       END AS status_bucket
 				FROM publish_records pr
+				LEFT JOIN platform_accounts pa ON pa.id = pr.platform_account_id
 				WHERE pr.tenant_id = a.tenant_id
 				  AND pr.article_id = a.id
 				  AND pr.deleted_at IS NULL
-				ORDER BY
-					COALESCE(pr.target_type, 'platform_account'),
-					COALESCE(pr.platform_account_id, pr.target_connection_id),
-					pr.created_at DESC,
-					pr.id DESC
+				ORDER BY ` + publishRecordTargetIdentityExprSQL + `, pr.created_at DESC, pr.id DESC
 			) latest
 		) publish_status_summary ON true`