fix: fetch full git history to resolve CodeQL diff range undefined values

- Add fetch-depth: 0 to checkout action to get complete git history
- This should prevent the pr-diff-range extension from generating undefined values
- The shallow clone was causing git diff calculations to fail

Author: joshrotenberg

.github/workflows/codeql.yml

@@ -30,6 +30,9 @@ jobs:
     steps:
       - name: Checkout repository
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683  # v4.2.2
+        with:
+          # Fetch more history to avoid diff range issues
+          fetch-depth: 0
 
       - name: Initialize CodeQL
         uses: github/codeql-action/init@ea9e4e37992a54ee68a9622e985e60c8e8f12d9f2  # v3.27.4