Refactor CI workflow to replace actions/checkout with custom checkout logic

.gitea/workflows/ci.yaml

@@ -10,7 +10,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        run: |
+          if [ -d /tmp/watch-party ]; then
+            cd /tmp/watch-party && git fetch origin && git reset --hard origin/main
+          else
+            git clone https://gitea.home.arpa/nik/watch-party /tmp/watch-party
+          fi
+          cp -r /tmp/watch-party/. .
 
       - name: Write deploy key
         run: |