Streak & home Added a sleep-based day streak with a month view and a tappable top bar; enlarged the profile avatar in the top bar. Apple Health Added a Body Battery estimator for Apple Health-only users, integrated into the sync pipeline (including backfill for records missing stress/battery estimates). Stress is now estimated from Apple Watch heart rate, sitting time is derived from stand-time data, and Apple Health "Core" sleep is counted as light sleep. Users are prompted to grant newly-added Apple Health metrics after app updates. Healthspan / vital age Replaced the old weighted model with an additive vital-age model: each metric's deviation from its healthy target contributes signed years that sum into the vital-age delta, fixing the long-standing bugs where "years younger" was stuck at 0.0 and pace of aging at 1.00X. Metrics are now tappable to reveal their scientific basis and nuance, a "Time Sitting" metric was added, and graph markers (6-month / 30-day averages) were made visible at the chart edges with the 30-day value shown below each marker. Added a clearer "The science" expand button and updated in-app explanations to describe the summation algorith