refactor: split agent.go into 12 files + add mcp_restart_server tool

internal/agent/core/plugins.go

@@ -0,0 +1,52 @@
+package core
+
+import (
+	"fmt"
+	"log"
+	"strings"
+)
+
+func (a *Agent) executePluginReload() string {
+	if a.pluginReg == nil {
+		return "插件系统未启用"
+	}
+	msg, err := a.pluginReg.Reload(a.pluginDir)
+	if err != nil {
+		return fmt.Sprintf("插件重载失败: %v", err)
+	}
+	return msg
+}
+
+func (a *Agent) autoReloadPlugins() {
+	if a.pluginReg == nil {
+		return
+	}
+	for _, name := range a.pluginHealth.pendingReloads() {
+		if !a.pluginReg.AutoRestartEnabled(name) {
+			log.Printf("[agent] skip auto-reload plugin %s: auto-restart disabled by plugin", name)
+			continue
+		}
+		log.Printf("[agent] auto-reloading unhealthy plugin: %s", name)
+		if a.stageHost != nil {
+			a.stageHost.UnregisterPluginTools(name)
+		}
+		if err := a.pluginReg.ReloadOne(name); err != nil {
+			log.Printf("[agent] auto-reload plugin %s failed: %v", name, err)
+		} else {
+			a.pluginHealth.markReloaded(name)
+			log.Printf("[agent] plugin %s reloaded successfully", name)
+		}
+	}
+}
+
+func (a *Agent) resolveToolPlugin(name string) string {
+	if a.stageHost != nil {
+		if plugin := a.stageHost.ToolPlugin(name); plugin != "" {
+			return plugin
+		}
+	}
+	if idx := strings.IndexByte(name, '_'); idx > 0 {
+		return name[:idx]
+	}
+	return "core"
+}