fix(ci): use fetch-depth: 0 for super-linter checkout

Super-linter needs the full git history to resolve GITHUB_BEFORE_SHA
(the previous commit SHA). With fetch-depth: 1 it fails with:
'The SHA_REFERENCE reference doesn't exist in this Git repository'

Author: dgibbs64

.github/workflows/action-super-linter.yml

@@ -27,9 +27,8 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v6
         with:
-          # Shallow clone reduces transient fetch failures (HTTP 500) from GitHub.
-          # We lint the whole codebase instead of relying on git history.
-          fetch-depth: 1
+          # Full clone required so super-linter can resolve GITHUB_BEFORE_SHA.
+          fetch-depth: 0
           fetch-tags: false
           persist-credentials: false