重构项目结构：统一目录层级

- 移除 backend/.git 工作树配置
- 将原根目录文件归入 backend/ 目录
- 新增 app/、frontend/ 等模块
- 保留文件历史（自动识别重命名）

backend/services/user-service/user-register-account/Cargo.toml

@@ -0,0 +1,33 @@
+[package]
+name = "user-register-account"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+axum = "0.8"
+tokio = { version = "1", features = ["full"] }
+tower = "0.5"
+
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
+
+sqlx = { version = "0.8", features = ["runtime-tokio", "tls-rustls", "postgres", "chrono", "uuid"] }
+
+# UUID
+uuid = { version = "1", features = ["v7", "serde"] }
+redis = { version = "0.29", features = ["tokio-comp"] }
+
+bcrypt = "0.17"
+
+chrono = { version = "0.4", features = ["serde"] }
+tracing = "0.1"
+tracing-subscriber = { version = "0.3", features = ["env-filter"] }
+
+dotenvy = "0.15"
+thiserror = "2.0"
+validator = { version = "0.20", features = ["derive"] }
+
+[profile.release]
+opt-level = 3
+lto = true
+strip = true