feat: Enhance dependency injection and service integration

- Updated main.go to initialize email service and include it in the dependency injection container.
- Refactored handlers to utilize context in service method calls, improving consistency and error handling.
- Introduced new service options for upload, security, and captcha services, enhancing modularity and testability.
- Removed unused repository implementations to streamline the codebase.

This commit continues the effort to improve the architecture by ensuring all services are properly injected and utilized across the application.

internal/service/verification_service_test.go

@@ -7,6 +7,9 @@ import (
 
 // TestGenerateVerificationCode 测试生成验证码函数
 func TestGenerateVerificationCode(t *testing.T) {
+	// 创建服务实例（使用 nil，因为这个测试不需要依赖）
+	svc := &verificationService{}
+
 	tests := []struct {
 		name    string
 		wantLen int
@@ -21,18 +24,18 @@ func TestGenerateVerificationCode(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			code, err := GenerateVerificationCode()
+			code, err := svc.generateCode()
 			if (err != nil) != tt.wantErr {
-				t.Errorf("GenerateVerificationCode() error = %v, wantErr %v", err, tt.wantErr)
+				t.Errorf("generateCode() error = %v, wantErr %v", err, tt.wantErr)
 				return
 			}
 			if !tt.wantErr && len(code) != tt.wantLen {
-				t.Errorf("GenerateVerificationCode() code length = %v, want %v", len(code), tt.wantLen)
+				t.Errorf("generateCode() code length = %v, want %v", len(code), tt.wantLen)
 			}
 			// 验证验证码只包含数字
 			for _, c := range code {
 				if c < '0' || c > '9' {
-					t.Errorf("GenerateVerificationCode() code contains non-digit: %c", c)
+					t.Errorf("generateCode() code contains non-digit: %c", c)
 				}
 			}
 		})
@@ -41,9 +44,9 @@ func TestGenerateVerificationCode(t *testing.T) {
 	// 测试多次生成，验证码应该不同（概率上）
 	codes := make(map[string]bool)
 	for i := 0; i < 100; i++ {
-		code, err := GenerateVerificationCode()
+		code, err := svc.generateCode()
 		if err != nil {
-			t.Fatalf("GenerateVerificationCode() failed: %v", err)
+			t.Fatalf("generateCode() failed: %v", err)
 		}
 		if codes[code] {
 			t.Logf("发现重复验证码（这是正常的，因为只有6位数字）: %s", code)
@@ -82,9 +85,10 @@ func TestVerificationConstants(t *testing.T) {
 
 // TestVerificationCodeFormat 测试验证码格式
 func TestVerificationCodeFormat(t *testing.T) {
-	code, err := GenerateVerificationCode()
+	svc := &verificationService{}
+	code, err := svc.generateCode()
 	if err != nil {
-		t.Fatalf("GenerateVerificationCode() failed: %v", err)
+		t.Fatalf("generateCode() failed: %v", err)
 	}
 
 	// 验证长度