Implement Task Search Functionality

**Description:**  
Add search capability to quickly find tasks by title, description, or tags.

**Tasks:**
- [ ] Add search bar UI component
- [ ] Implement search in `TodoDao` with query
- [ ] Add search functionality to `HomeScreenViewModel`
- [ ] Add search history (optional)
- [ ] Highlight search results

**Files to explore:**
- `TodoDao.kt`
- `HomeScreenViewModel.kt`
- `HomeScreen.kt`
