v0.7.5 — Calendar sync and upcoming workout dates

Fix the home mini calendar placing upcoming workouts on incorrect dates after a workout is completed late or its calendar completion date is missing.

• Batch sync now preserves workout and rest-day completion dates instead of clearing them when replacing calendar entries.
• Calendar scheduling and sync recover workout completion dates from the recorded session finish time. Marking an older workout finished today keeps it on its actual workout date.
• The mini calendar and day details use the same corrected schedule, preserving spacing between upcoming workouts and rest days.

Validation: calendar and sync regression checks, TypeScript, and production build passed.