fix(action): enhance JSON handling in matrix generation with jq fallback

.github/workflows/prepare.yml

@@ -49,16 +49,19 @@ jobs:
             echo "Error: Config file not found: ${{ inputs.config_file }}"
             exit 1
           fi
-
+          
+          # Read the file content
           MATRIX_JSON=$(cat "${{ inputs.config_file }}")
-
+          
+          # Compact the JSON to a single line to avoid issues
+          # If jq is not available, we might need another way, but ubuntu-latest usually has it.
           if command -v jq &> /dev/null; then
-            MATRIX_JSON=$(echo "$MATRIX_JSON" | jq -c '[.include[].kernel_version]')
+            MATRIX_JSON=$(echo "$MATRIX_JSON" | jq -c .)
           else
-            echo "jq not found, cannot build matrix."
-            exit 1
+            # Fallback for simple minification if jq missing (unlikely on runner)
+            MATRIX_JSON=$(echo "$MATRIX_JSON" | tr -d '\n' | tr -d ' ')
           fi
-
+          
           echo "Matrix content: $MATRIX_JSON"
           echo "matrix=$MATRIX_JSON" >> $GITHUB_OUTPUT