fix: 从后端恢复 Runner claim

internal/opensandboxbackend/backend.go

@@ -108,6 +108,30 @@ type Backend struct {
 	Config    Config
 }
 
+func (b Backend) RecoverAssignments(ctx context.Context, trustDomain string) ([]taskassignment.Assignment, error) {
+	if err := b.validate(); err != nil {
+		return nil, err
+	}
+	result, err := b.Lifecycle.ListSandboxes(ctx, opensandbox.ListOptions{
+		Metadata: map[string]string{"ci.ddupan.top/backend": "vm"}, PageSize: 100,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("list recoverable sandboxes: %w", err)
+	}
+	assignments := make([]taskassignment.Assignment, 0, len(result.Items))
+	for _, sandbox := range result.Items {
+		if sandbox.Metadata[terminalMetadata] == "true" {
+			continue
+		}
+		assignment, err := taskassignment.FromMetadata(sandbox.Metadata, sandbox.Metadata, trustDomain)
+		if err != nil {
+			return nil, fmt.Errorf("recover sandbox %s: %w", sandbox.ID, err)
+		}
+		assignments = append(assignments, assignment)
+	}
+	return assignments, nil
+}
+
 func NewLifecycleClient(baseURL, apiKey string, client *http.Client) *opensandbox.LifecycleClient {
 	if client != nil {
 		return opensandbox.NewLifecycleClient(baseURL, apiKey, opensandbox.WithHTTPClient(client))