Complete CRUD operations for habits

Implement all missing endpoints for full habit management:
- GET /api/v1/habits - List all user habits
- GET /api/v1/habits/{id} - Get specific habit
- PUT /api/v1/habits/{id} - Update habit
- DELETE /api/v1/habits/{id} - Archive habit (soft delete)
- GET /api/v1/habits/{id}/entries - Get habit entry history
- DELETE /api/v1/habits/{id}/entries/{date} - Unmark habit (soft delete entry)

All endpoints include:
- TDD approach with comprehensive test coverage
- JWT authentication and ownership validation
- Proper error handling (404, 403, 400, 500)
- Clean architecture with separated commands/queries

internal/application/queries/get_user_habits.go

@@ -0,0 +1,53 @@
+package queries
+
+import (
+	"context"
+
+	"apocapoc-api/internal/domain/repositories"
+)
+
+type HabitDTO struct {
+	ID           string
+	Name         string
+	Type         string
+	Frequency    string
+	TargetValue  *float64
+	CarryOver    bool
+	SpecificDays []int
+}
+
+type GetUserHabitsQuery struct {
+	UserID string
+}
+
+type GetUserHabitsHandler struct {
+	habitRepo repositories.HabitRepository
+}
+
+func NewGetUserHabitsHandler(habitRepo repositories.HabitRepository) *GetUserHabitsHandler {
+	return &GetUserHabitsHandler{
+		habitRepo: habitRepo,
+	}
+}
+
+func (h *GetUserHabitsHandler) Handle(ctx context.Context, query GetUserHabitsQuery) ([]HabitDTO, error) {
+	habits, err := h.habitRepo.FindActiveByUserID(ctx, query.UserID)
+	if err != nil {
+		return nil, err
+	}
+
+	var result []HabitDTO
+	for _, habit := range habits {
+		result = append(result, HabitDTO{
+			ID:           habit.ID,
+			Name:         habit.Name,
+			Type:         string(habit.Type),
+			Frequency:    string(habit.Frequency),
+			TargetValue:  habit.TargetValue,
+			CarryOver:    habit.CarryOver,
+			SpecificDays: habit.SpecificDays,
+		})
+	}
+
+	return result, nil
+}