feat(core): implement StaticConfig/DynamicConfig split with ArcSwap hot-reload

Split alknet-core configuration into StaticConfig (immutable after startup)
and DynamicConfig (hot-reloadable at runtime via ArcSwap).

- Add StaticConfig struct in config/static_config.rs with all fields per ADR-030
- Add DynamicConfig struct with AuthPolicy, ForwardingPolicy, RateLimitConfig
- Add ForwardingPolicy with allow_all()/deny_all() defaults (ADR-031)
- Add ConfigReloadHandle with reload() method for runtime config updates
- Replace Arc<ServerAuthConfig> with Arc<ArcSwap<DynamicConfig>> in ServerHandler
- Add config_reload_handle() to Server for obtaining reload handles
- Add AuthPolicy with authenticate_publickey/authenticate_certificate methods
- All existing tests pass with the new config structure
- Default DynamicConfig produces identical behavior to current code

crates/alknet-core/src/socks5/protocol.rs

@@ -169,10 +169,7 @@ mod tests {
         let req = Socks5Request::read_from(&mut cursor).await.unwrap();
         assert_eq!(req.version, 0x05);
         assert_eq!(req.command, 0x01);
-        assert_eq!(
-            req.address,
-            Socks5Address::Ipv4(Ipv4Addr::new(10, 0, 0, 1))
-        );
+        assert_eq!(req.address, Socks5Address::Ipv4(Ipv4Addr::new(10, 0, 0, 1)));
         assert_eq!(req.port, 443);
     }
 
@@ -201,7 +198,10 @@ mod tests {
         let req = Socks5Request::read_from(&mut cursor).await.unwrap();
         assert_eq!(req.version, 0x05);
         assert_eq!(req.command, 0x01);
-        assert_eq!(req.address, Socks5Address::Domain("example.com".to_string()));
+        assert_eq!(
+            req.address,
+            Socks5Address::Domain("example.com".to_string())
+        );
         assert_eq!(req.port, 443);
     }
 
@@ -301,4 +301,4 @@ mod tests {
         let port = cursor.read_u16().await.unwrap();
         assert_eq!(port, 8080);
     }
-}
+}