Mock Training Log test fixture

This is a vgym test endpoint — not Strava. No login, no branding. The proof reads the JSON at /athlete/training_activities?activity_type=Run&page=1.

ActivityTypeDateDistance
Mock run 1RunTue Aug 11 20263.20 km
Mock run 2RunMon Aug 10 20262.10 km
Mock run 3RunSun Aug 09 20261.25 km