feat(cli): 优化 log 子命令并引入 LogLevel 强类型解析,重构 commands.lua 注册表解析与校验逻辑

- 调整 LogLevel 的 FromStr 错误类型为 String，适配 clap 的 value_parser
- log 子命令直接绑定 LogLevel 枚举，消除硬编码校验与类型转换
- 规范化日志级别更新与配置读取逻辑
- handler 类型有 Function 改为 String

mirror-cli/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "mirror-cli"
+version = { workspace = true }
+edition = { workspace = true }
+
+# 显式指定生成的二进制文件名
+[[bin]]
+name = "mr"
+path = "src/main.rs"
+
+[dependencies]
+mirror-core = { path = "../mirror-core" }
+clap = { version = "4.6.6", features = ["cargo", "color", "derive","string"] }
+clap_derive = { version = "4.6.4" }
+mlua = { workspace = true }
+anyhow = { workspace = true }
+tracing = { workspace = true }
+tracing-subscriber = { workspace = true }