docs(mcp): 存量英文注释中文化（仅注释，代码零字节改动）

- capability/mcp 整包 17 个文件核查：仅 config.go / registry.go 含英文注释（38 行）→ 全部中文化；
  其余 15 个文件本就全中文，零改动。
- 保留 YAML/Go/JSON 示例行与字符串字面量（非注释，禁止改动）。
- 验收：机械校验为空；gofmt -l 干净；go build/vet/test ./internal/capability/mcp/... 全绿。

internal/capability/mcp/registry.go

@@ -10,8 +10,8 @@ import (
 	"git.yeij.top/AskaEth/Cyrene_v2/internal/capability/registry"
 )
 
-// Registry connects an MCP client and auto-registers its discovered tools into
-// the shared capability registry, making them available to every character.
+// Registry 连接一台 MCP 客户端，把自动发现的工具注册进共享的 capability
+// registry，使所有角色都能使用。
 type Registry struct {
 	reg    *registry.Registry
 	mcp    *Client
@@ -21,11 +21,10 @@ type Registry struct {
 	closed bool
 }
 
-// NewRegistry builds a Registry that registers cfg's tools into reg. Options
-// apply to the underlying Client (logger, injected transport). It is named
-// NewRegistry rather than New because this package already exports New for
-// Client. A tool-list-changed handler is wired automatically so the registry
-// re-syncs when the server announces tools/list_changed.
+// NewRegistry 构建一个 Registry，把 cfg 的工具注册进 reg。opts 作用在底层
+// Client 上（日志器、注入的传输）。之所以叫 NewRegistry 而不是 New，是因为
+// 本包已为 Client 导出了 New。这里会自动接上工具清单变更回调，
+// 服务器发 tools/list_changed 时 registry 会重新同步。
 func NewRegistry(reg *registry.Registry, cfg MCPConfig, opts ...Option) *Registry {
 	r := &Registry{reg: reg}
 	opts = append(opts, WithToolListChangedHandler(r.refresh))
@@ -35,8 +34,7 @@ func NewRegistry(reg *registry.Registry, cfg MCPConfig, opts ...Option) *Registr
 	return r
 }
 
-// Register connects the MCP server, discovers its tools, and registers each one
-// into the underlying registry.
+// Register 连接 MCP 服务器、发现其工具，并把每把工具注册进底层 registry。
 func (r *Registry) Register(ctx context.Context) error {
 	if r.reg == nil {
 		return fmt.Errorf("mcp registry: nil registry")
@@ -64,12 +62,10 @@ func (r *Registry) Register(ctx context.Context) error {
 	return nil
 }
 
-// refresh re-syncs the registered tool set with the server after a
-// notifications/tools/list_changed notification. It re-discovers the current
-// tools and applies only the diff: it removes names that are gone and registers
-// newly appeared ones, so tools registered by other providers (which collide by
-// name) are preserved. It is invoked (off the transport read path) by the
-// client's tool-list-changed handler and coalesced by the client.
+// refresh 在收到 notifications/tools/list_changed 通知后，把已注册工具集与
+// 服务器重新对齐。它重新发现当前工具并只应用差异：移除已消失的名字、
+// 注册新出现的名字，因此其它提供者注册的同名工具（名字冲突）会被保留。
+// 它由客户端的工具清单变更回调调用（不在传输读路径上），并由客户端合并触发。
 func (r *Registry) refresh() {
 	if r.reg == nil {
 		return
@@ -91,9 +87,8 @@ func (r *Registry) refresh() {
 		return
 	}
 
-	// Drop names the server no longer exposes. Tools registered by other
-	// providers were skipped at registration time and are not in r.names, so they
-	// are never removed here.
+	// 丢弃服务器不再暴露的名字。其它提供者注册的工具在注册时就被跳过、
+	// 不在 r.names 里，因此这里永远不会把它们删掉。
 	kept := r.names[:0]
 	for _, name := range r.names {
 		if !incoming[name] {
@@ -106,8 +101,8 @@ func (r *Registry) refresh() {
 	}
 	r.names = kept
 
-	// Register newly appeared tools. Skips names already present (own or
-	// foreign) so a name collision with another provider is not doubled.
+	// 注册新出现的工具。跳过已存在的名字（无论是自己的还是外来的），
+	// 避免与其它提供者同名时重复注册。
 	existing := make(map[string]bool, len(r.names))
 	for _, name := range r.names {
 		existing[name] = true
@@ -127,16 +122,16 @@ func (r *Registry) refresh() {
 	r.log.Info("mcp tools refreshed", "name", r.mcp.cfg.Name, "count", len(r.names))
 }
 
-// ToolNames returns a copy of the tool names this registry registered, in
-// registration order. It is empty before Register succeeds.
+// ToolNames 返回本 registry 注册过的工具名副本（按注册顺序）。
+// Register 成功之前为空。
 func (r *Registry) ToolNames() []string {
 	r.mu.Lock()
 	defer r.mu.Unlock()
 	return append([]string(nil), r.names...)
 }
 
-// Unregister removes every tool this registry previously registered and closes
-// the underlying client. It is safe to call multiple times.
+// Unregister 移除本 registry 之前注册的全部工具，并关闭底层客户端。
+// 可安全重复调用。
 func (r *Registry) Unregister(ctx context.Context) error {
 	r.mu.Lock()
 	names := r.names