Add task templates API and admin management

- Add TaskTemplate model with category and frequency support
- Add task template repository with CRUD and search operations
- Add task template service layer
- Add public API endpoints for templates (no auth required):
  - GET /api/tasks/templates/ - list all templates
  - GET /api/tasks/templates/grouped/ - templates grouped by category
  - GET /api/tasks/templates/search/?q= - search templates
  - GET /api/tasks/templates/by-category/:id/ - templates by category
  - GET /api/tasks/templates/:id/ - single template
- Add admin panel for task template management (CRUD)
- Add admin API endpoints for templates
- Add seed file with predefined task templates
- Add i18n translations for template errors

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

internal/services/task_template_service.go

@@ -0,0 +1,69 @@
+package services
+
+import (
+	"github.com/treytartt/casera-api/internal/dto/responses"
+	"github.com/treytartt/casera-api/internal/repositories"
+)
+
+// TaskTemplateService handles business logic for task templates
+type TaskTemplateService struct {
+	templateRepo *repositories.TaskTemplateRepository
+}
+
+// NewTaskTemplateService creates a new task template service
+func NewTaskTemplateService(templateRepo *repositories.TaskTemplateRepository) *TaskTemplateService {
+	return &TaskTemplateService{
+		templateRepo: templateRepo,
+	}
+}
+
+// GetAll returns all active task templates
+func (s *TaskTemplateService) GetAll() ([]responses.TaskTemplateResponse, error) {
+	templates, err := s.templateRepo.GetAll()
+	if err != nil {
+		return nil, err
+	}
+	return responses.NewTaskTemplateListResponse(templates), nil
+}
+
+// GetGrouped returns all templates grouped by category
+func (s *TaskTemplateService) GetGrouped() (responses.TaskTemplatesGroupedResponse, error) {
+	templates, err := s.templateRepo.GetAll()
+	if err != nil {
+		return responses.TaskTemplatesGroupedResponse{}, err
+	}
+	return responses.NewTaskTemplatesGroupedResponse(templates), nil
+}
+
+// Search searches templates by query string
+func (s *TaskTemplateService) Search(query string) ([]responses.TaskTemplateResponse, error) {
+	templates, err := s.templateRepo.Search(query)
+	if err != nil {
+		return nil, err
+	}
+	return responses.NewTaskTemplateListResponse(templates), nil
+}
+
+// GetByCategory returns templates for a specific category
+func (s *TaskTemplateService) GetByCategory(categoryID uint) ([]responses.TaskTemplateResponse, error) {
+	templates, err := s.templateRepo.GetByCategory(categoryID)
+	if err != nil {
+		return nil, err
+	}
+	return responses.NewTaskTemplateListResponse(templates), nil
+}
+
+// GetByID returns a single template by ID
+func (s *TaskTemplateService) GetByID(id uint) (*responses.TaskTemplateResponse, error) {
+	template, err := s.templateRepo.GetByID(id)
+	if err != nil {
+		return nil, err
+	}
+	resp := responses.NewTaskTemplateResponse(template)
+	return &resp, nil
+}
+
+// Count returns the total count of active templates
+func (s *TaskTemplateService) Count() (int64, error) {
+	return s.templateRepo.Count()
+}