feat: add functionality to manage deleted projects in settings

- Introduced a new section for displaying soft-deleted projects.
- Implemented loading of deleted projects via an API call.
- Added restore and permanently delete options for each deleted project.
- Integrated loading of deleted projects when the data tab is shown.

backend/routers/projects.py

@@ -654,6 +654,40 @@ async def create_project(request: Request, db: Session = Depends(get_db)):
     })
 
 
+@router.get("/deleted")
+async def list_deleted_projects(db: Session = Depends(get_db)):
+    """List all soft-deleted projects."""
+    projects = (
+        db.query(Project)
+        .filter(Project.status == "deleted")
+        .order_by(Project.deleted_at.desc())
+        .all()
+    )
+    return JSONResponse([
+        {
+            "id": p.id,
+            "name": p.name,
+            "client_name": p.client_name,
+            "deleted_at": p.deleted_at.isoformat() if p.deleted_at else None,
+        }
+        for p in projects
+    ])
+
+
+@router.post("/{project_id}/restore")
+async def restore_project(project_id: str, db: Session = Depends(get_db)):
+    """Restore a soft-deleted project back to active."""
+    project = db.query(Project).filter_by(id=project_id).first()
+    if not project:
+        raise HTTPException(status_code=404, detail="Project not found")
+    if project.status != "deleted":
+        raise HTTPException(status_code=400, detail="Project is not deleted")
+    project.status = "active"
+    project.deleted_at = None
+    db.commit()
+    return {"success": True, "message": f"Project '{project.name}' restored."}
+
+
 @router.get("/{project_id}")
 async def get_project(project_id: str, db: Session = Depends(get_db)):
     """