Habit Settings: Add Habit Priority Levels

Why this is useful:
Not all habits are equally important. Some—like going to the gym, studying, or sleeping early—directly support long-term goals. Others—like rearranging your bookshelf or watching a YouTube video—are nice but not essential.

Right now, all habits in Habitify look the same. But in real life, we often have limited time and energy.

- Priority levels (High, Medium, Low) would help us focus on what really matters.

Example:
On a busy day, “Go to the gym” and “Shower” are clearly more important than “Reorganize bookshelf” or “Watch a YouTube video.” Giving habits a priority makes it easier to stay consistent with what truly improves our life, without guilt for skipping the less critical ones.

This would help users stay focused, flexible, and aligned with their goals.