feat(build): add CLA section and Dependabot security prefix workflow

- Add Contributor License Agreement section to root CONTRIBUTING.md
- Add workflow to retitle Dependabot security PRs with security(deps) prefix

Closes #236, Closes #237

📝 - Generated by Copilot

Author: Bill Berry

.github/workflows/dependabot-security-prefix.yml

@@ -0,0 +1,40 @@
+name: Dependabot Security Prefix
+
+on:
+  pull_request:
+    types:
+      - opened
+
+permissions:
+  contents: read
+  pull-requests: write
+
+jobs:
+  retitle-security-pr:
+    name: Retitle Security PRs
+    runs-on: ubuntu-latest
+    if: github.actor == 'dependabot[bot]'
+    permissions:
+      contents: read
+      pull-requests: write
+
+    steps:
+      - name: Fetch Dependabot metadata
+        id: metadata
+        uses: dependabot/fetch-metadata@21025c705c08248db411dc16f3619e6b5f9ea21a # v2.5.0
+        with:
+          github-token: "${{ secrets.GITHUB_TOKEN }}"
+
+      - name: Retitle PR with security prefix
+        if: steps.metadata.outputs.ghsa-id != '' || steps.metadata.outputs.cvss != ''
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          PR_NUMBER: ${{ github.event.pull_request.number }}
+          PR_TITLE: ${{ github.event.pull_request.title }}
+        run: |
+          new_title="${PR_TITLE/chore(deps)/security(deps)}"
+          new_title="${new_title/chore(deps-dev)/security(deps-dev)}"
+          if [[ "${new_title}" != "${PR_TITLE}" ]]; then
+            gh pr edit "${PR_NUMBER}" --repo "${GITHUB_REPOSITORY}" --title "${new_title}"
+            echo "Retitled PR #${PR_NUMBER}: ${new_title}"
+          fi

CONTRIBUTING.md

@@ -15,6 +15,14 @@ Contributions are welcome across infrastructure code, deployment automation, doc
 
 If you are new to the project, start with issues labeled `good first issue` or documentation updates before making larger changes.
 
+## Contributor License Agreement
+
+Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit <https://cla.opensource.microsoft.com>.
+
+When you submit a pull request, a CLA bot will automatically determine whether you need to provide a CLA and decorate the PR appropriately (e.g., status check, comment). Follow the instructions provided by the bot. You only need to do this once across all repos using our CLA.
+
+This project has adopted the [Microsoft Open Source Code of Conduct](https://opensource.microsoft.com/codeofconduct/). For more information see the [Code of Conduct FAQ](https://opensource.microsoft.com/codeofconduct/faq/) or contact [opencode@microsoft.com](mailto:opencode@microsoft.com) with any questions or comments.
+
 ## Getting Started
 
 1. Read the [Contributing Guide](docs/contributing/README.md) for prerequisites, workflow, and conventions