ci: add diagnostic steps to verify registry secrets are accessible

.gitea/workflows/build.yaml

@@ -49,10 +49,35 @@ jobs:
           SHORT_SHA=$(git rev-parse --short HEAD)
           echo "short_sha=${SHORT_SHA}" >> $GITHUB_OUTPUT
 
+      - name: Verify registry secrets
+        run: |
+          echo "=== Registry Login Diagnostic ==="
+          if [ -z "${REGISTRY_USER}" ]; then
+            echo "❌ ERROR: FORGEJO_REGISTRY_USER secret is empty/not set"
+            exit 1
+          fi
+          if [ -z "${REGISTRY_TOKEN}" ]; then
+            echo "❌ ERROR: FORGEJO_REGISTRY_TOKEN secret is empty/not set"
+            exit 1
+          fi
+          echo "✓ REGISTRY_USER is set (length: ${#REGISTRY_USER})"
+          echo "✓ REGISTRY_TOKEN is set (length: ${#REGISTRY_TOKEN})"
+          echo "✓ Registry: ${REGISTRY}"
+          echo "=== Attempting login test ==="
+        env:
+          REGISTRY_USER: ${{ secrets.FORGEJO_REGISTRY_USER }}
+          REGISTRY_TOKEN: ${{ secrets.FORGEJO_REGISTRY_TOKEN }}
+
       - name: Registry login
         run: |
           echo "${REGISTRY_TOKEN}" | docker login "${REGISTRY}" \
-            --username "${REGISTRY_USER}" --password-stdin
+            --username "${REGISTRY_USER}" --password-stdin 2>&1
+          if [ $? -eq 0 ]; then
+            echo "✓ Login successful"
+          else
+            echo "❌ Login failed"
+            exit 1
+          fi
         env:
           REGISTRY_USER: ${{ secrets.FORGEJO_REGISTRY_USER }}
           REGISTRY_TOKEN: ${{ secrets.FORGEJO_REGISTRY_TOKEN }}