fix: Fix artifact action compatibility and add digest debugging

Resolve upload-artifact v4 GHES compatibility errors by downgrading to v3.
Switch to standard forgejo/download-artifact@v4 for pattern filtering support.
Update renovate configuration to prevent future incompatible upgrades.

Add diagnostic output to digest export step to troubleshoot zero-byte
artifact uploads preventing manifest creation. Include CI triggers for
Element workflow to test changes in pull requests.

.forgejo/workflows/element.yml

@@ -4,6 +4,14 @@ on:
   schedule:
     - cron: "0 0 * * *"
   workflow_dispatch:
+  pull_request:
+    paths:
+      - ".forgejo/workflows/element.yml"
+  push:
+    branches:
+      - main
+    paths:
+      - ".forgejo/workflows/element.yml"
 
 concurrency:
   group: "element-${{ github.ref }}"
@@ -101,7 +109,7 @@ jobs:
           cat ./element-web/webapp/config.json
 
       - name: 📤 Upload Artifact
-        uses: https://code.forgejo.org/actions/upload-artifact@v4
+        uses: https://code.forgejo.org/actions/upload-artifact@v3
         with:
           name: element-web
           path: ./element-web/webapp/

.forgejo/workflows/release-image.yml

@@ -234,14 +234,24 @@ jobs:
         run: |
           mkdir -p /tmp/digests
           digest="${{ steps.build.outputs.digest }}"
-          touch "/tmp/digests/${digest#sha256:}"
+          echo "🔍 Build step digest output: '$digest'"
+          if [[ -z "$digest" ]]; then
+            echo "❌ ERROR: No digest found from build step"
+            exit 1
+          fi
+          digest_file="/tmp/digests/${digest#sha256:}"
+          echo "📁 Creating digest file: $digest_file"
+          touch "$digest_file"
+          echo "✅ Digest file created successfully"
+          echo "📋 Contents of /tmp/digests:"
+          ls -la /tmp/digests/
 
       # Binary extracted via local output for all builds
       - name: Rename extracted binary
         run: mv /tmp/binaries/sbin/conduwuit /tmp/binaries/conduwuit-${{ matrix.target_cpu }}-${{ matrix.slug }}-${{ matrix.profile }}
 
       - name: Upload binary artifact
-        uses: forgejo/upload-artifact@v4
+        uses: forgejo/upload-artifact@v3
         with:
           name: conduwuit-${{ matrix.target_cpu }}-${{ matrix.slug }}-${{ matrix.profile }}
           path: /tmp/binaries/conduwuit-${{ matrix.target_cpu }}-${{ matrix.slug }}-${{ matrix.profile }}
@@ -249,7 +259,7 @@ jobs:
 
       - name: Upload digest
         if: ${{ env.BUILTIN_REGISTRY_ENABLED == 'true' }}
-        uses: forgejo/upload-artifact@v4
+        uses: forgejo/upload-artifact@v3
         with:
           name: digests-${{ matrix.slug }}
           path: /tmp/digests/*