refactor: migrate built-in plugins to SDK-only interface

- Six-phase plan complete: webui/cli/healthcheck/pluginmgr/clawhubadapter
  now interact with the kernel exclusively via internal/sdk interfaces;
  all Configure() calls and package-level global injection removed
- buildSDK in internal/plugin/registry.go is the single assembly point
- Add internal/sdk/events.go exporting event types/constants
- Fix ProviderManager cooldown sharing: LuaAdaptedProvider.Name() now
  returns the source name instead of lua_<adapter>, so multiple sources
  sharing an adapter (single script load via shared VM AdapterCache) no
  longer share failure-cooldown state
- Verified: build/vet/tests green, deployed to homeagent.service with
  full plugin capability testing via local OpenAI-compatible mock

internal/sdk/tool_impl.go

@@ -0,0 +1,50 @@
+package sdk
+
+import (
+	"fmt"
+
+	agentIO "gitcode.com/JianFeeeee/HomeAgent/internal/agent/io"
+)
+
+// toolImpl 桥接 StageHost（插件工具）与 IOManager（设备/通道工具）。
+type toolImpl struct {
+	stageHost ToolSource
+	iom       *agentIO.IOManager
+}
+
+func NewTool(sh ToolSource, iom *agentIO.IOManager) ToolAPI {
+	return &toolImpl{stageHost: sh, iom: iom}
+}
+
+func (t *toolImpl) GetToolDefs() []ToolDef {
+	if t.stageHost == nil {
+		return nil
+	}
+	return t.stageHost.GetToolDefs()
+}
+
+func (t *toolImpl) GetAllTools() []ToolDef {
+	if t.iom == nil {
+		return nil
+	}
+	defs := t.iom.GetAllTools()
+	out := make([]ToolDef, 0, len(defs))
+	for _, d := range defs {
+		out = append(out, ToolDef{Name: d.Name, Description: d.Description, Parameters: d.Parameters})
+	}
+	return out
+}
+
+func (t *toolImpl) ExecuteTool(name string, args map[string]interface{}) (interface{}, error) {
+	if t.stageHost != nil {
+		if def := t.stageHost.ToolDef(name); def != nil {
+			return t.stageHost.ExecuteTool(name, args)
+		}
+	}
+	if t.iom != nil {
+		return t.iom.ExecuteTool(name, args)
+	}
+	return nil, fmt.Errorf("tool %s not found", name)
+}
+
+var _ ToolAPI = (*toolImpl)(nil)