fix(ui): add CUSTOM_ROUTER_PATH support in general settings

- Add CUSTOM_ROUTER_PATH field to UI configuration
  - Fix configuration preservation during save operations

ui/src/components/ConfigProvider.tsx

@@ -103,7 +103,8 @@ export function ConfigProvider({ children }: ConfigProviderProps) {
             longContext: '',
             longContextThreshold: 60000,
             webSearch: ''
-          }
+          },
+          CUSTOM_ROUTER_PATH: typeof data.CUSTOM_ROUTER_PATH === 'string' ? data.CUSTOM_ROUTER_PATH : ''
         };
         
         setConfig(validConfig);
@@ -132,7 +133,8 @@ export function ConfigProvider({ children }: ConfigProviderProps) {
               longContext: '',
               longContextThreshold: 60000,
               webSearch: ''
-            }
+            },
+            CUSTOM_ROUTER_PATH: ''
           });
           setError(err as Error);
         }

ui/src/components/SettingsDialog.tsx

@@ -212,6 +212,21 @@ export function SettingsDialog({ isOpen, onOpenChange }: SettingsDialogProps) {
               className="transition-all-ease focus:scale-[1.01]"
             />
           </div>
+          <div className="space-y-2">
+            <Label
+              htmlFor="custom-router-path"
+              className="transition-all-ease hover:scale-[1.01] cursor-pointer"
+            >
+              {t("toplevel.custom_router_path")}
+            </Label>
+            <Input
+              id="custom-router-path"
+              value={config.CUSTOM_ROUTER_PATH || ""}
+              onChange={(e) => setConfig({ ...config, CUSTOM_ROUTER_PATH: e.target.value })}
+              placeholder={t("toplevel.custom_router_path_placeholder")}
+              className="transition-all-ease focus:scale-[1.01]"
+            />
+          </div>
         </div>
         <DialogFooter className="p-4 pt-0">
           <Button