Upgrade frontend to Node 26, React 19, Vite 8, Apollo Client 4 and ESLint 10

.gitea/workflows/tests.yml

@@ -7,7 +7,7 @@ on:
 jobs:
   build_frontend:
     runs-on: ubuntu-latest
-    container: node:20-alpine
+    container: node:26-alpine
     steps:
       - uses: actions/checkout@v4
       - name: Build frontend
@@ -18,7 +18,7 @@ jobs:
 
   tests:
     runs-on: ubuntu-latest
-    container: nikolaik/python-nodejs:python3.14-nodejs20
+    container: nikolaik/python-nodejs:python3.14-nodejs26
     steps:
       - uses: actions/checkout@v4