ci: update actions to Node 24 runtime

.github/workflows/ci.yml

@@ -6,17 +6,14 @@ on:
   pull_request:
     branches: [main]
 
-env:
-  FORCE_JAVASCRIPT_ACTIONS_TO_NODE24: "true"
-
 jobs:
   backend:
     name: Backend (lint + tests + compose)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
 
-      - uses: actions/setup-python@v5
+      - uses: actions/setup-python@v6
         with:
           python-version: "3.11"
           cache: "pip"
@@ -65,9 +62,9 @@ jobs:
       run:
         working-directory: frontend
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
 
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v5
         with:
           node-version: "20"
           cache: "npm"