fix: add ResolveRenameOp to handle directory renames

RenameNode was calling Resolve() which generated blob keys for
directories that don't have blobs, causing 'key not found' errors.

Added ResolveRenameOp to BlobKeyResolver interface:
- FlatKeyResolver returns nil (UUIDs don't change on rename)
- HierarchicalKeyResolver returns move op for files and directories

This allows directory renames to work correctly with flat storage,
and leverages os.Rename for atomic directory moves with hierarchical.

Co-authored-by: Ona <no-reply@ona.com>

apps/backend/internal/virtualfs/flat_key_resolver.go

@@ -45,3 +45,9 @@ func (r *FlatKeyResolver) ResolveBulkMoveOps(ctx context.Context, db bun.IDB, no
 	}
 	return nil, nil
 }
+
+// ResolveRenameOp returns nil for flat key storage since blob keys are UUIDs
+// and don't change when nodes are renamed.
+func (r *FlatKeyResolver) ResolveRenameOp(ctx context.Context, db bun.IDB, node *Node, newName string) (*BlobMoveOp, error) {
+	return nil, nil
+}

apps/backend/internal/virtualfs/hierarchical_key_resolver.go

@@ -77,3 +77,34 @@ func (r *HierarchicalKeyResolver) ResolveBulkMoveOps(ctx context.Context, db bun
 
 	return ops, nil
 }
+
+// ResolveRenameOp returns the blob move operation for renaming a node.
+// For hierarchical storage, both files and directories need blob moves since
+// the key is path-based. os.Rename handles directory moves atomically.
+func (r *HierarchicalKeyResolver) ResolveRenameOp(ctx context.Context, db bun.IDB, node *Node, newName string) (*BlobMoveOp, error) {
+	oldPath, err := buildNodeAbsolutePathString(ctx, db, node)
+	if err != nil {
+		return nil, err
+	}
+
+	parentPath, err := buildPathFromNodeID(ctx, db, node.ParentID)
+	if err != nil {
+		return nil, err
+	}
+
+	var newPath string
+	if parentPath == "" {
+		newPath = newName
+	} else {
+		newPath = fmt.Sprintf("%s/%s", parentPath, newName)
+	}
+
+	oldKey := blob.Key(fmt.Sprintf("%s/%s", node.DriveID, oldPath))
+	newKey := blob.Key(fmt.Sprintf("%s/%s", node.DriveID, newPath))
+
+	return &BlobMoveOp{
+		Node:   node,
+		OldKey: oldKey,
+		NewKey: newKey,
+	}, nil
+}

apps/backend/internal/virtualfs/key_resolver.go

@@ -20,6 +20,12 @@ type BlobKeyResolver interface {
 	// Returns ErrBulkMoveRequiresSameParent if nodes don't all share the same parent.
 	// Returns nil, nil if no blob moves are needed (e.g., flat key storage where keys are UUIDs).
 	ResolveBulkMoveOps(ctx context.Context, db bun.IDB, nodes []*Node, newParentID uuid.UUID) ([]BlobMoveOp, error)
+
+	// ResolveRenameOp returns the blob move operation needed when renaming a node.
+	// Returns nil, nil if no blob move is needed (e.g., flat key storage where keys are UUIDs).
+	// For hierarchical storage, returns a single move op for both files and directories
+	// (os.Rename handles directories atomically).
+	ResolveRenameOp(ctx context.Context, db bun.IDB, node *Node, newName string) (*BlobMoveOp, error)
 }
 
 type DeletionPlan struct {

apps/backend/internal/virtualfs/vfs.go

@@ -598,7 +598,8 @@ func (vfs *VirtualFS) RenameNode(ctx context.Context, db bun.IDB, node *Node, na
 		return ErrAccessDenied
 	}
 
-	oldKey, err := vfs.keyResolver.Resolve(ctx, db, node)
+	// Resolve rename operation before updating DB (needs old path)
+	renameOp, err := vfs.keyResolver.ResolveRenameOp(ctx, db, node, name)
 	if err != nil {
 		return err
 	}
@@ -617,22 +618,18 @@ func (vfs *VirtualFS) RenameNode(ctx context.Context, db bun.IDB, node *Node, na
 		return err
 	}
 
-	newKey, err := vfs.keyResolver.Resolve(ctx, db, node)
-	if err != nil {
-		return err
-	}
-
-	if oldKey != newKey {
-		err = vfs.blobStore.Move(ctx, oldKey, newKey)
+	// Execute blob move if needed
+	if renameOp != nil {
+		err = vfs.blobStore.Move(ctx, renameOp.OldKey, renameOp.NewKey)
 		if err != nil {
 			return err
 		}
 
 		if vfs.keyResolver.ShouldPersistKey() {
-			node.BlobKey = newKey
+			node.BlobKey = renameOp.NewKey
 			_, err = db.NewUpdate().Model(node).
 				WherePK().
-				Set("blob_key = ?", newKey).
+				Set("blob_key = ?", renameOp.NewKey).
 				Exec(ctx)
 			if err != nil {
 				return err