dependencies: remove cypress from package.json

Cypress is huge. npm still attempts to install optional dependencies.

It shall be installed manually if frontend testing is needed.

.github/workflows/test-frontend.yml

@@ -20,7 +20,7 @@ jobs:
 
       - run: sudo apt-get install -y rtorrent
 
-      - run: sudo npm i -g wait-on
+      - run: sudo npm i -g wait-on cypress
       - run: npm ci
       - run: npm run build
 

package.json

@@ -201,10 +201,6 @@
     "yargs": "^16.0.3",
     "zod": "^1.11.9"
   },
-  "optionalDependencies": {
-    "cypress": "^5.4.0",
-    "start-server-and-test": "^1.11.5"
-  },
   "eslintConfig": {
     "extends": "react-app"
   },