Add pagination support to GET /api/v1/habits endpoint

- Create pagination package with Params and Response structs
- Add FindActiveByUserIDWithPagination and CountActiveByUserID methods to HabitRepository interface
- Implement pagination in SQLite repository using LIMIT and OFFSET
- Update GetUserHabitsHandler to support optional pagination parameters
- Modify HTTP endpoint to parse 'page' and 'page_size' query params (default: page=1, page_size=50, max=100)
- Add GetUserHabitsResponse DTO with pagination metadata
- Maintain backward compatibility - endpoint works with and without pagination params
- Add comprehensive tests for pagination logic in repository, handler, and pagination package
- Update all mock repositories to implement new pagination methods

internal/application/commands/create_habit_test.go

@@ -1,6 +1,7 @@
 package commands
 
 import (
+	"apocapoc-api/internal/shared/pagination"
 	"context"
 	"testing"
 
@@ -229,3 +230,11 @@ func TestCreateHabitHandler_NegativeHabit(t *testing.T) {
 		t.Error("Expected habit ID to be returned")
 	}
 }
+
+func (m *mockHabitRepo) FindActiveByUserIDWithPagination(ctx context.Context, userID string, params pagination.Params) ([]*entities.Habit, error) {
+	return nil, nil
+}
+
+func (m *mockHabitRepo) CountActiveByUserID(ctx context.Context, userID string) (int, error) {
+	return 0, nil
+}