🌱 Update golangci-lint to v2.8.0

The previous version (v2.1.6) had false positives with staticcheck
not recognizing that t.Fatal() terminates execution, causing spurious
"possible nil pointer dereference" warnings in test files.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Signed-off-by: Andrew Anderson <andy@clubanderson.com>

Author: clubanderson

.github/workflows/ci-pr-checks.yaml

@@ -31,7 +31,7 @@ jobs:
       - name: Install golangci-lint
         uses: golangci/golangci-lint-action@v8
         with:
-          version: v2.1.6
+          version: v2.8.0
           args: ""
 
       - name: Run make build