Feat v0.3.4 team roles signoff (#18)

Co-authored-by: Jeffrey Smith <jasafpro@gmail.com>
Co-committed-by: Jeffrey Smith <jasafpro@gmail.com>

server/store/postgres/workflows.go

@@ -660,6 +660,48 @@ func (s *WorkflowStore) ListAssignmentsByUser(ctx context.Context, userID string
 	return s.queryAssignments(ctx, q, args...)
 }
 
+// ── Signoffs (v0.3.4) ─────────────────────────
+
+func (s *WorkflowStore) CreateSignoff(ctx context.Context, so *models.WorkflowSignoff) error {
+	return DB.QueryRowContext(ctx, `
+		INSERT INTO workflow_signoffs (instance_id, stage, user_id, decision, comment)
+		VALUES ($1, $2, $3, $4, $5)
+		RETURNING id, created_at`,
+		so.InstanceID, so.Stage, so.UserID, so.Decision, so.Comment,
+	).Scan(&so.ID, &so.CreatedAt)
+}
+
+func (s *WorkflowStore) ListSignoffs(ctx context.Context, instanceID, stage string) ([]models.WorkflowSignoff, error) {
+	rows, err := DB.QueryContext(ctx, `
+		SELECT id, instance_id, stage, user_id, decision, comment, created_at
+		FROM workflow_signoffs
+		WHERE instance_id = $1 AND stage = $2
+		ORDER BY created_at`, instanceID, stage)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var result []models.WorkflowSignoff
+	for rows.Next() {
+		var so models.WorkflowSignoff
+		if err := rows.Scan(&so.ID, &so.InstanceID, &so.Stage, &so.UserID,
+			&so.Decision, &so.Comment, &so.CreatedAt); err != nil {
+			return nil, err
+		}
+		result = append(result, so)
+	}
+	return result, rows.Err()
+}
+
+func (s *WorkflowStore) CountSignoffs(ctx context.Context, instanceID, stage, decision string) (int, error) {
+	var count int
+	err := DB.QueryRowContext(ctx, `
+		SELECT COUNT(*) FROM workflow_signoffs
+		WHERE instance_id = $1 AND stage = $2 AND decision = $3`,
+		instanceID, stage, decision).Scan(&count)
+	return count, err
+}
+
 func (s *WorkflowStore) queryAssignments(ctx context.Context, q string, args ...interface{}) ([]models.WorkflowAssignment, error) {
 	rows, err := DB.QueryContext(ctx, q, args...)
 	if err != nil {