Add debug output to ai-prereview-guard workflow

[jolelievre]

Questions	Answers
Branch?	master
Description?	Add diagnostic output to the check-membership step in the ai-prereview-guard reusable workflow to help debug token and permission issues.
Type?	improvement
Category?	CO
BC breaks?	no
Deprecations?	no
How to test?	1. Trigger the ai-prereview workflow on a test PR in ps_apiresources with the Need AI review label 2. Check the step summary for debug output (token availability, HTTP status, response body) 3. Verify that an empty token produces a clear error message instead of a silent failure
UI Tests
Fixed issue or discussion?	Related to PrestaShop/PrestaShop#41245
Related PRs	PrestaShop/ps_apiresources#194
Sponsor company	PrestaShop SA

Details

Changes to check-membership step

• Early exit with a clear ::error:: annotation when the org-read-token secret is empty
• Log token length and prefix (masked) to the step summary to confirm the secret is being passed
• Log the API URL being called
• Log the full HTTP response body on failure (not just the status code) to help diagnose 401/403/404 errors
• Log membership role and state on success for additional confirmation