Program workouts built by buildProgramWorkouts() were missing level,
rounds, calories, and other Workout-interface fields, causing
workout.level.toLowerCase() to crash on the detail, collection, and
category screens. Added derived defaults (level from week number,
category from program id, standard Tabata timings) and defensive
fallbacks with ?? 'Beginner' at all call sites. Also fixed a potential
division-by-zero when exercises array is empty.
f11eb6b9ae