refactor(server): decouple services and improve architecture

- Introduce interfaces for all major services (JWT, PostAI, Comment, Message, Notification, QRCodeLogin, Upload, Vote, etc.) to support dependency inversion.
- Move query parameters from `internal/dto` to a new `internal/query` package to separate request payloads from data transfer objects.
- Refactor `internal/router` to use embedded `RouterDeps` for cleaner dependency management.
- Decouple handlers from repositories by injecting services instead of direct repository access, ensuring proper layering.
- Improve database initialization by moving it from `internal/model` to `internal/database`.
- Optimize message decryption by implementing a more efficient `BatchDecrypt` method in `MessageEncryptor` using a worker pool.
- Enhance error handling and security by implementing fail-fast checks for encryption key length during startup.
- Clean up unused code, including the `avatar` package and several unused DTOs.

internal/handler/grade_handler.go

@@ -4,19 +4,16 @@ import (
 	"github.com/gin-gonic/gin"
 
 	"with_you/internal/pkg/response"
-	"with_you/internal/repository"
 	"with_you/internal/service"
 )
 
 type GradeHandler struct {
 	gradeSyncService service.GradeSyncService
-	gradeRepo        repository.GradeRepository
 }
 
-func NewGradeHandler(gradeSyncService service.GradeSyncService, gradeRepo repository.GradeRepository) *GradeHandler {
+func NewGradeHandler(gradeSyncService service.GradeSyncService) *GradeHandler {
 	return &GradeHandler{
 		gradeSyncService: gradeSyncService,
-		gradeRepo:        gradeRepo,
 	}
 }
 
@@ -63,16 +60,14 @@ func (h *GradeHandler) ListGrades(c *gin.Context) {
 		return
 	}
 
-	grades, err := h.gradeRepo.ListByUser(userID)
+	summary, err := h.gradeSyncService.ListGradesWithSummary(userID)
 	if err != nil {
 		response.HandleError(c, err, "failed to list grades")
 		return
 	}
 
-	gpaSummary, _ := h.gradeRepo.GetLatestGpaSummary(userID)
-
 	response.Success(c, gin.H{
-		"grades":      grades,
-		"gpa_summary": gpaSummary,
+		"grades":      summary.Grades,
+		"gpa_summary": summary.GpaSummary,
 	})
 }