chore(deps): Bump actions/checkout from 6 to 7 (#24)

Bumps [actions/checkout](https://github.com/actions/checkout) from 6 to 7.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v6...v7)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -18,7 +18,7 @@ jobs:
     name: Validate Skills
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
 
       - name: Check marketplace.json is valid JSON
         run: python3 -c "import json; json.load(open('.claude-plugin/marketplace.json'))"

.github/workflows/codeql.yml

@@ -23,7 +23,7 @@ jobs:
       contents: read
       security-events: write
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - uses: github/codeql-action/init@v4
         with:
           languages: actions