Add NAPI reload API for DynamicConfig and ForwardingPolicy

- Add reloadAuth(), reloadForwarding(), reloadAll() methods to AlknetServer
- Add NAPI type definitions: AuthConfigNapi, ForwardingPolicyConfig, ForwardingRuleConfig
- Refactor NapiServerHandler to use ArcSwap<DynamicConfig> for atomic config swaps
- Add ConfigReloadHandle::dynamic_arc() accessor for sharing ArcSwap between NAPI and accept loop
- Add ipnetwork dependency to alknet-napi for TargetPattern CIDR parsing
- Add builder functions for AuthPolicy and ForwardingPolicy from NAPI config types
- All swaps are atomic via ArcSwap per ADR-030

crates/alknet-core/src/config/dynamic_config.rs

@@ -277,6 +277,10 @@ impl ConfigReloadHandle {
     pub fn dynamic(&self) -> Arc<DynamicConfig> {
         self.dynamic.load_full()
     }
+
+    pub fn dynamic_arc(&self) -> Arc<ArcSwap<DynamicConfig>> {
+        Arc::clone(&self.dynamic)
+    }
 }
 
 impl std::fmt::Debug for ConfigReloadHandle {