feat(ci): add CLAUDE.md and improve claude-code-action workflows

- Add CLAUDE.md with lerobot-specific review instructions (core abstractions,
  engineering principles, ML-specific checks, PR checklist)
- Enable use_sticky_comment: true on both workflows (single updating comment per PR)
- Add structured lerobot-specific review prompt to claude-code-review.yml
- Upgrade permissions: contents/pull-requests/issues write for interactive claude.yml
- Add actions: read to claude-code-review.yml for CI log access
- Set FORCE_JAVASCRIPT_ACTIONS_TO_NODE24: true to suppress Node.js 20 deprecation warnings

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.github/workflows/claude.yml

@@ -19,11 +19,14 @@ jobs:
       (github.event_name == 'issues' && (contains(github.event.issue.body, '@claude') || contains(github.event.issue.title, '@claude')))
     runs-on: ubuntu-latest
     permissions:
-      contents: read
-      pull-requests: read
-      issues: read
+      contents: write
+      pull-requests: write
+      issues: write
       id-token: write
-      actions: read # Required for Claude to read CI results on PRs
+      actions: read
+    env:
+      FORCE_JAVASCRIPT_ACTIONS_TO_NODE24: true
+
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
@@ -36,14 +39,12 @@ jobs:
         uses: anthropics/claude-code-action@26ddc358fe3befff50c5ec2f80304c90c763f6f8 # v1
         with:
           anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}
+          use_sticky_comment: true
 
           # This is an optional setting that allows Claude to read CI results on PRs
           additional_permissions: |
             actions: read
 
-          # Optional: Give a custom prompt to Claude. If this is not specified, Claude will perform the instructions specified in the comment that tagged it.
-          # prompt: 'Update the pull request description to include a summary of changes.'
-
           # Optional: Add claude_args to customize behavior and configuration
           # See https://github.com/anthropics/claude-code-action/blob/main/docs/usage.md
           # or https://code.claude.com/docs/en/cli-reference for available options