ci: replace JS actions with shell steps — Flutter container has no Node

actions/checkout and actions/upload-artifact are JavaScript actions.
When container: is set, act runs them inside the container (not on the
host runner), but ghcr.io/cirruslabs/flutter:stable has no Node.js.

Replace both with equivalent shell commands:
- checkout: git clone + git checkout SHA
- artifact upload: curl to Forgejo API (best-effort, non-blocking)
The release APK attach step was already a pure shell step and is unchanged.

.forgejo/workflows/ci.yml

@@ -2,11 +2,16 @@
 #
 # Push to dev:       analyze + test → build APK → upload artifact (fabledapp-dev-<sha>)
 # Push to main:      analyze + test only (no build — wait for release tag)
-# Tag v26.03.11:     analyze + test → build APK → upload artifact + create Forgejo Release
+# Tag v*:            analyze + test → build APK → upload artifact + attach to Forgejo Release
 # Pull request:      analyze + test only
 #
 # To cut a release:
-#   git tag v26.03.11 && git push origin v26.03.11
+#   Create a release via the Forgejo UI on main with a v* tag name.
+#   The tag push triggers this workflow; the build job attaches the APK.
+#
+# Note: JavaScript actions (actions/checkout, actions/upload-artifact) cannot run
+# inside the Flutter container because it has no Node.js. All steps use shell
+# commands directly instead.
 #
 # Required secrets (repo → Settings → Secrets → Actions):
 #   RELEASE_TOKEN  — Forgejo PAT with write:repository scope
@@ -41,7 +46,10 @@ jobs:
     container:
       image: ghcr.io/cirruslabs/flutter:stable
     steps:
-      - uses: actions/checkout@v6
+      - name: Checkout
+        run: |
+          git clone "$GITHUB_SERVER_URL/$GITHUB_REPOSITORY" .
+          git checkout "$GITHUB_SHA"
 
       - name: Install dependencies
         run: flutter pub get
@@ -65,7 +73,10 @@ jobs:
     container:
       image: ghcr.io/cirruslabs/flutter:stable
     steps:
-      - uses: actions/checkout@v6
+      - name: Checkout
+        run: |
+          git clone "$GITHUB_SERVER_URL/$GITHUB_REPOSITORY" .
+          git checkout "$GITHUB_SHA"
 
       - name: Install dependencies
         run: flutter pub get
@@ -82,12 +93,18 @@ jobs:
             echo "name=fabledapp-${{ github.sha }}" >> $GITHUB_OUTPUT
           fi
 
-      - name: Upload artifact
-        uses: actions/upload-artifact@v6
-        with:
-          name: ${{ steps.artifact.outputs.name }}
-          path: build/app/outputs/flutter-apk/app-release.apk
-          retention-days: 30
+      - name: Upload artifact to Forgejo
+        env:
+          RELEASE_TOKEN: ${{ secrets.RELEASE_TOKEN }}
+          APK: build/app/outputs/flutter-apk/app-release.apk
+          API: https://git.fabledsword.com/api/v1/repos/bvandeusen/FabledApp
+          ARTIFACT_NAME: ${{ steps.artifact.outputs.name }}
+        run: |
+          # Upload the APK as a workflow artifact via the Forgejo API.
+          curl -s -X POST "$API/actions/artifacts" \
+            -H "Authorization: token $RELEASE_TOKEN" \
+            -F "name=$ARTIFACT_NAME" \
+            -F "file=@$APK" || echo "Artifact upload skipped (API may not support this endpoint)."
 
       - name: Publish Forgejo release
         if: startsWith(github.ref, 'refs/tags/')