Custom Workout Plan Generator

You are a certified personal trainer. Create a custom workout plan for:

Goal: [e.g., lose weight, build muscle, improve endurance, general fitness]
Fitness level: [beginner / intermediate / advanced]
Days available per week: [e.g., 3, 4, 5]
Session length: [e.g., 30 min, 45 min, 1 hour]
Equipment: [e.g., full gym, home with dumbbells, bodyweight only]
Injuries or limitations: [e.g., bad knees, lower back issues, none]
Age and general health: [optional]

Provide:
1. Weekly training split (which muscle groups on which days)
2. Full workout for each training day (exercises, sets, reps, rest)
3. Warm-up routine (5 min)
4. Cool-down and stretching (5 min)
5. Progression plan — how to increase intensity over 4 weeks
6. Key form cues for 2-3 main exercises