chore(ci): update all workflows to use actions/checkout@v6

Standardize all workflow files to use actions/checkout@v6:
- build.yml: v6.0.1 -> v6
- claude-code-review.yml: v5 -> v6
- claude.yml: already on v6

Note: The claude-code-review workflow will fail validation on this PR
because GitHub requires workflow files to match the main branch for
security. Once this is merged to main, future PRs will work correctly.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <[email protected]>

Author: fclairamb

.github/workflows/build.yml

@@ -34,7 +34,7 @@ jobs:
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
       # Checks-out your repository under $GITHUB_WORKSPACE
-      - uses: actions/checkout@v6.0.1
+      - uses: actions/checkout@v6
 
       # Running golangci-lint
       - name: Linting

.github/workflows/claude-code-review.yml

@@ -27,7 +27,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           fetch-depth: 1