Turn your real schedule into a workout routine you'll actually keep

Act as a personal trainer who builds realistic routines for people with limited time, not
magazine-cover routines nobody actually keeps. I'm going to give you my schedule, my level,
and my goal. Your job is to build a routine I can genuinely stick to, not the "ideal" one I
quit on in two weeks.

My context:
- Real days and times I can work out (be specific, with an approximate time):
  [E.G. MONDAY 6:30AM, WEDNESDAY 7PM, SATURDAY MORNING]
- How much time I have on each of those days: [E.G. 30 MIN ON WEEKDAYS, 45 ON SATURDAY]
- My current level: [BEGINNER / INTERMEDIATE / ADVANCED / RETURNING AFTER A LONG BREAK]
- My main goal: [E.G. LOSE WEIGHT, BUILD STRENGTH, MORE ENERGY, TONE UP]
- Equipment I have available: [NONE / DUMBBELLS / BANDS / FULL GYM]
- Injuries or limitations to avoid (if any): [E.G. KNEE, LOWER BACK, OR "NONE"]

With that information, build a 3 to 4 day routine that respects EXACTLY the days and minutes I
gave you (don't give me a 5-day routine if I only have 3 available). For each day include:
1. **Warm-up** (2-3 minutes, concrete exercises).
2. **Main block** with the name of each exercise, sets, reps or time, and a short form note
   when the exercise is prone to a common mistake.
3. **Cool-down** (stretching or short cardio, 2-3 minutes).
4. An easier and a harder alternative for at least 2 exercises per day, in case I'm not
   performing as well one day or want to raise the intensity.

At the end add:
- A weekly summary table (day, total duration, day's focus in 2-3 words).
- A short note on how to progress the routine over 3-4 weeks without me having to redesign it
  from scratch.

Rules:
- Don't add days or time I didn't give you. If my time or equipment doesn't allow for a
  typical exercise for that goal, adjust or substitute it, don't force it in.
- If I mentioned an injury or limitation, fully avoid exercises that would aggravate it and
  say so explicitly at the bottom of the routine.
- Don't promise results in a specific timeframe (e.g. "you'll see changes in 2 weeks"); focus
  on making the routine sustainable.