Add Agentic Workflows as a new resource type

Add support for contributing Agentic Workflows — AI-powered repository
automations that run coding agents in GitHub Actions, defined in markdown
with natural language instructions (https://github.github.com/gh-aw).

Changes:
- Create workflows/ directory for community-contributed workflows
- Add workflow metadata parsing (yaml-parser.mjs)
- Add workflow README generation (update-readme.mjs, constants.mjs)
- Add workflow data to website generation (generate-website-data.mjs)
- Update README.md, CONTRIBUTING.md, and AGENTS.md with workflow docs,
  contributing guidelines, and code review checklists

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

docs/README.workflows.md

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+# ⚡ Agentic Workflows
+
+[Agentic Workflows](https://github.github.com/gh-aw) are AI-powered repository automations that run coding agents in GitHub Actions. Defined in markdown with natural language instructions, they enable event-triggered and scheduled automation with built-in guardrails and security-first design.
+
+### How to Use Agentic Workflows
+
+**What's Included:**
+- Each workflow is a folder containing a `README.md` and one or more `.md` workflow files
+- Workflows are compiled to `.lock.yml` GitHub Actions files via `gh aw compile`
+- Workflows follow the [GitHub Agentic Workflows specification](https://github.github.com/gh-aw)
+
+**To Install:**
+- Install the `gh aw` CLI extension: `gh extension install github/gh-aw`
+- Copy the workflow `.md` file to your repository's `.github/workflows/` directory
+- Compile with `gh aw compile` to generate the `.lock.yml` file
+- Commit both the `.md` and `.lock.yml` files
+
+**To Activate/Use:**
+- Workflows run automatically based on their configured triggers (schedules, events, slash commands)
+- Use `gh aw run <workflow>` to trigger a manual run
+- Monitor runs with `gh aw status` and `gh aw logs`
+
+**When to Use:**
+- Automate issue triage and labeling
+- Generate daily status reports
+- Maintain documentation automatically
+- Run scheduled code quality checks
+- Respond to slash commands in issues and PRs
+- Orchestrate multi-step repository automation
+
+_No entries found yet._