feat: 重构 DHT 爬取与可观测性

src/error.rs

@@ -1,21 +1,28 @@
 use thiserror::Error;
 
 #[derive(Error, Debug)]
+/// Error returned during DHT initialization or execution.
 pub enum DHTError {
+    /// Socket or other network I/O failed.
     #[error("网络错误: {0}")]
     Network(#[from] std::io::Error),
 
+    /// A shared lock was poisoned.
     #[error("锁中毒: {0}")]
     LockPoisoned(String),
 
+    /// Server initialization failed, for example because a socket could not bind.
     #[error("初始化错误: {0}")]
     Init(String),
 
+    /// An internal invariant or worker operation failed.
     #[error("内部错误: {0}")]
     Internal(String),
 
+    /// Another error represented by a human-readable message.
     #[error("{0}")]
     Other(String),
 }
 
+/// Result type used by the crate's public APIs.
 pub type Result<T> = std::result::Result<T, DHTError>;