BACKEND : Capsule 32: Daily Story Capsule

### 📖 Overview
Users must write a short story daily for 3 days to unlock.

### ✍️ Feature Description
- Word count > 100.
- Cannot submit same story.
- Auto-compare text similarity to block cheating.

### 🛠️ Tasks
- [ ] Build story submission form.
- [ ] Store daily logs.
- [ ] Integrate plagiarism detection API or algorithm.