feat: update ingest, registry, and UI flows

internal/repository/timeline/events.go

@@ -102,3 +102,66 @@ func (r *EventRepository) List(ctx context.Context, subjectType string, subjectI
 
 	return events, nextCursor, nil
 }
+
+func (r *EventRepository) ListLatestBySubjects(ctx context.Context, subjectType string, ids []string) (map[string]domain.TimelineEvent, error) {
+	result := make(map[string]domain.TimelineEvent, len(ids))
+	if len(ids) == 0 {
+		return result, nil
+	}
+
+	placeholders := make([]string, len(ids))
+	args := make([]any, 0, len(ids)+1)
+	args = append(args, subjectType)
+	for i, id := range ids {
+		placeholders[i] = "?"
+		args = append(args, id)
+	}
+
+	query := `
+		SELECT t.id, t.subject_id, t.event_type, t.event_time, t.machine_id, t.part_id, t.firmware_version, t.created_at
+		FROM timeline_events t
+		WHERE t.subject_type = ? AND t.subject_id IN (` + strings.Join(placeholders, ",") + `)
+		  AND NOT EXISTS (
+			SELECT 1
+			FROM timeline_events t2
+			WHERE t2.subject_type = t.subject_type
+			  AND t2.subject_id = t.subject_id
+			  AND (
+				t2.event_time > t.event_time
+				OR (t2.event_time = t.event_time AND t2.id > t.id)
+			  )
+		  )
+	`
+
+	rows, err := r.db.QueryContext(ctx, query, args...)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	for rows.Next() {
+		var event domain.TimelineEvent
+		event.SubjectType = subjectType
+		var machineID sql.NullString
+		var partID sql.NullString
+		var firmware sql.NullString
+		if err := rows.Scan(&event.ID, &event.SubjectID, &event.EventType, &event.EventTime, &machineID, &partID, &firmware, &event.CreatedAt); err != nil {
+			return nil, err
+		}
+		if machineID.Valid {
+			event.MachineID = &machineID.String
+		}
+		if partID.Valid {
+			event.PartID = &partID.String
+		}
+		if firmware.Valid {
+			event.FirmwareVersion = &firmware.String
+		}
+		result[event.SubjectID] = event
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+
+	return result, nil
+}