用户服务 4 个 crate 合并为单一 user-service，按 DDD 限界上下文聚合

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/services/user-service/Cargo.toml

@@ -0,0 +1,48 @@
+[package]
+name = "user-service"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+# Web 框架
+axum = "0.8"
+tokio = { version = "1", features = ["full"] }
+tower = "0.5"
+
+# 序列化
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
+
+# 数据库
+sqlx = { version = "0.8", features = ["runtime-tokio", "tls-rustls", "postgres", "chrono", "uuid"] }
+
+# UUID
+uuid = { version = "1", features = ["v7", "serde"] }
+
+# Redis（预留：当前未使用，待引入限流/会话等场景）
+redis = { version = "0.29", features = ["tokio-comp"] }
+
+# 密码哈希
+bcrypt = "0.17"
+
+# JWT
+jsonwebtoken = "9.3"
+
+# 时间和日志
+chrono = { version = "0.4", features = ["serde"] }
+tracing = "0.1"
+tracing-subscriber = { version = "0.3", features = ["env-filter"] }
+
+# 环境变量
+dotenvy = "0.15"
+
+# 错误处理
+thiserror = "2.0"
+
+# 参数校验
+validator = { version = "0.20", features = ["derive"] }
+
+[profile.release]
+opt-level = 3
+lto = true
+strip = true