refactor: Rewrite major parts of the file browser

The UI was completely messed up and is fixed now. Folders and files
are aligned again.

In addition, workspace is now expanded by default, new code style has been
applied and the deprecated `NestedTreeControl` was replaced.

backend/capellacollab/core/responses.py

@@ -178,3 +178,39 @@ class SVGResponse(fastapi.responses.Response):
             }
         }
     }
+
+
+class ZIPFileResponse(fastapi.responses.StreamingResponse):
+    """Custom error class for zip-file responses.
+
+    To use the class as response class, pass the following parameters
+    to the fastapi route definition.
+
+    ```python
+    response_class=fastapi.responses.Response
+    responses=responses.ZIPFileResponse.responses
+    ```
+
+    Don't use ZIPFileResponse as response_class as this will also change the
+    media type for all error responses, see:
+    https://github.com/tiangolo/fastapi/discussions/6799
+
+    To return an ZIP-file response in the route, use:
+
+    ```python
+    return responses.SVGResponse(
+        content=b"<svg>...</svg>",
+    )
+    ```
+    """
+
+    media_type = "application/zip"
+    responses: dict[int | str, dict[str, t.Any]] | None = {
+        200: {
+            "content": {
+                "application/zip": {
+                    "schema": {"type": "string", "format": "binary"}
+                }
+            }
+        }
+    }

backend/capellacollab/sessions/files/routes.py

@@ -9,6 +9,7 @@
 import fastapi
 from fastapi import responses
 
+from capellacollab.core import responses as core_responses
 from capellacollab.sessions import injectables as sessions_injectables
 from capellacollab.sessions import models as sessions_models
 from capellacollab.sessions import operators
@@ -69,17 +70,17 @@ def upload_files(
     return {"message": "Upload successful"}
 
 
-@router.get("/download", response_class=responses.StreamingResponse)
+@router.get(
+    "/download",
+    response_class=responses.StreamingResponse,
+    responses=core_responses.ZIPFileResponse.responses,
+)
 def download_file(
     filename: str,
     session: sessions_models.DatabaseSession = fastapi.Depends(
         sessions_injectables.get_existing_session
     ),
-) -> responses.StreamingResponse:
-    return responses.StreamingResponse(
+) -> core_responses.ZIPFileResponse:
+    return core_responses.ZIPFileResponse(
         operators.get_operator().download_file(session.id, filename),
-        headers={
-            "content-disposition": 'attachment; filename=f"{filename}.zip"',
-            "content-type": "application/zip",
-        },
     )

frontend/src/app/sessions/service/session.service.ts

@@ -9,6 +9,7 @@ import {
   SessionProvisioningRequest,
   SessionsService,
   SessionConnectionInformation,
+  FileTree,
 } from 'src/app/openapi';
 import { SessionHistoryService } from 'src/app/sessions/user-sessions-wrapper/create-sessions/create-session-history/session-history.service';
 
@@ -223,10 +224,8 @@ export interface SessionState {
   success: boolean;
 }
 
-export interface PathNode {
-  path: string;
-  name: string;
-  type: 'file' | 'directory';
-  isNew: boolean;
+export type PathNode = FileTree & {
+  isNew?: boolean;
+  isExpanded?: boolean;
   children: PathNode[] | null;
-}
+};