Make repo fork-save

If this repo is forked, push the rendered pages to the forked repo,
not to the original.
Also make sure the rendered gitea link points to the forked repo.

.gitea/workflows/deploy-pages.yml

@@ -16,7 +16,9 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Build page
-        run: /opt/python-env/bin/zensical build
+        run: |
+            sed -i 's|repo_url[[:space:]]*=[[:space:]]*".*"|repo_url = "${{ github.server_url }}/${{ github.repository }}"|' zensical.toml
+            /opt/python-env/bin/zensical build
       
       - name: Configure Git
         run: |
@@ -30,5 +32,6 @@ jobs:
           mv site/* .
           git add .
           git commit -m "Update site - $(date)"
-          git push -f https://${{secrets.GITHUB_TOKEN}}@gitea.psi.ch/Controls/gitea-pages.git gitea-pages
+          REPO_URL=$(echo "${{ github.server_url }}/${{ github.repository }}.git" | sed 's|https://||')
+          git push -f https://${{ secrets.GITHUB_TOKEN }}@$REPO_URL gitea-pages