Program builder — redesigned, mobile-first

The program builder is rebuilt around how coaches actually work on a phone (grounded in a 180-source review of the best coaching tools):

• Day strip. Swipe across your training days as pills with a live exercise count; tap to edit one day at a time. Add or duplicate a day in a tap (up to 7).
• Clean exercise cards. Each exercise is its own card with the full prescription laid out — Sets, rep range, Load, RPE, Rest — plus reorder and remove.
• Add-exercise sheet. A bottom sheet with instant search (by name, muscle, or equipment), a muscle filter, and a Recent list of what you use most — tap to add several in a row.
• Autosave, no Save button. Every change saves on its own; a status shows "Saving… / Saved", with one-tap retry if you're offline. You can't lose work.
• Duplicate day to reuse a structure across the week without retyping.

This is the foundation for what's next: offline client logging, exercise substitution, and supersets.