Add markdown formatting guidelines to create-agentic-workflow template

.github/aw/create-agentic-workflow.md

@@ -352,3 +352,9 @@ Include in the PR description:
 - Always follow security best practices (least privilege, safe outputs, constrained network)
 - The body of the markdown file is a prompt, so use best practices for prompt engineering
 - Skip verbose summaries at the end, keep it concise
+- **Markdown formatting guidelines**: When creating workflow prompts that generate reports or documentation output, include these markdown formatting guidelines:
+  - Use GitHub-flavored markdown (GFM) for all output
+  - **Headers**: Start at h3 (###) to maintain proper document hierarchy
+  - **Checkboxes**: Use `- [ ]` for unchecked and `- [x]` for checked task items
+  - **Progressive Disclosure**: Use `<details><summary><b>Bold Summary Text</b></summary>` to collapse long content
+  - **Workflow Run Links**: Format as `[§12345](https://github.com/owner/repo/actions/runs/12345)`. Do NOT add footer attribution (system adds automatically)