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/pkg/crypto/message_encryptor_test.go

@@ -150,16 +150,6 @@ func TestMessageEncryptor_KeyVersion(t *testing.T) {
 	if encryptor.GetKeyVersion() != 1 {
 		t.Errorf("GetKeyVersion() = %d, want 1", encryptor.GetKeyVersion())
 	}
-
-	// 测试密钥轮换
-	err = encryptor.RotateKey("abcdefghijklmnopqrstuvwxyz123456", 2)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	if encryptor.GetKeyVersion() != 2 {
-		t.Errorf("GetKeyVersion() after rotation = %d, want 2", encryptor.GetKeyVersion())
-	}
 }
 
 func mustMarshal(v interface{}) []byte {