Offline screenshots are not attached for users with ID 10 or higher #420

Summary

Offline screenshots are never attached for users with ID 10 or higher.

Details

uploadOfflineScreenshots (app/Http/Controllers/Api/IntervalController.php) takes the user ID from the screenshot file name <user_id>_<screenshot_uuid> with Str::of($path)->match('/\d_.+/'). The pattern matches only the last digit before _, so 57_<uuid> is parsed as user 7; the interval lookup by user_id + screenshot_id then finds nothing and the screenshot is reported as not attached (or, if user 7 exists and owns that screenshot id, attached to the wrong user).

Acceptance criteria

• File names are parsed as ^(\d+)_(<uuid>)$ on the base name; anything else is rejected as a wrong file name.
• Tests cover single- and multi-digit user IDs.