fix: add markdownlint config and auto-fix markdown errors

- Add .markdownlint-cli2.jsonc based on headlamp-agent-skills config
- Disable MD013 (line length), MD041 (first-line-heading), MD036
  (emphasis-as-heading), MD024 (no-duplicate-heading), MD040
  (fenced-code-language), MD060 (table-column-style), MD029
  (ol-prefix), MD033 (no-inline-html) — appropriate for plugin docs
- Run markdownlint-cli2 --fix to auto-fix MD022, MD031, MD032
- Manually fix remaining code block language annotations

Co-Authored-By: Paperclip <noreply@paperclip.ing>

docs/troubleshooting/common-issues.md

@@ -703,6 +703,7 @@ If none of these solutions work, gather debugging information and open an issue:
    ```
 
 6. **RBAC Configuration**:
+
    ```bash
    kubectl get role,rolebinding -n polaris
    ```