Refactor habit entries: remove soft delete and add smart pagination

Remove soft delete from HabitEntry:
- Eliminate DeletedAt field from entity and database
- Change UnmarkHabit from soft delete to hard delete
- Simplify all queries removing deleted_at checks
- Update migration to remove deleted_at column

Add date filtering and smart pagination to GetHabitEntries:
- Support optional from/to date parameters
- Implement intelligent pagination rules:
  * No date range: pagination required
  * Date range > 1 year: pagination required
  * Date range ≤ 1 year: pagination optional
- Pagination defaults (page=1, limit=50) only when required
- Return metadata with total count, page, and limit

Technical improvements:
- Cleaner codebase without soft delete complexity
- Better performance (no filtering in queries)
- More intuitive API with flexible pagination
- Comprehensive test coverage for validation rules

internal/infrastructure/http/dto.go

@@ -69,6 +69,13 @@ type HabitEntryResponse struct {
 	Value         *float64  `json:"value,omitempty"`
 }
 
+type HabitEntriesResponse struct {
+	Entries []HabitEntryResponse `json:"entries"`
+	Total   int                  `json:"total"`
+	Page    int                  `json:"page"`
+	Limit   int                  `json:"limit"`
+}
+
 type ErrorResponse struct {
 	Error string `json:"error"`
 }