ci(forgejo): manual git checkout instead of actions/checkout@v4

The cirruslabs/flutter job image has no Node.js, so JS-based actions fail with
'exec: node: not found'. Check out with plain git over the internal forgejo:3000
URL + job token, keeping the workflows Node-free.

.forgejo/workflows/release.yml

@@ -26,8 +26,17 @@ jobs:
     container:
       image: ghcr.io/cirruslabs/flutter:3.41.9
     steps:
+      # Manual git checkout (no Node): the flutter image has no node, so JS
+      # actions like actions/checkout@v4 fail with "exec: node: not found".
       - name: Checkout
-        uses: actions/checkout@v4
+        env:
+          TOKEN: ${{ github.token }}
+        run: |
+          git config --global --add safe.directory '*'
+          git init -q .
+          git remote add origin "http://x-access-token:${TOKEN}@forgejo:3000/${GITHUB_REPOSITORY}.git"
+          git fetch -q --depth 1 origin "${GITHUB_SHA}"
+          git checkout -q FETCH_HEAD
 
       - name: Generate code (i18n + Drift)
         working-directory: apps/app_seeds