docs(comments): 注释中文化 · internal/runtime/multimodal（21 文件，纯替换）

- 只翻注释/文档字符串，代码零变化：go/scanner 词法流比对 21 文件 token+字面量全等，增删行数 1:1（467/467）
- 刻意保留非散文英文：JSON Schema description、工具 Description() 返回值、adapter prompt、API 路径与命令示例、环境变量名
- 逐行确认代码前缀未变，未触碰其他模块

internal/runtime/multimodal/vision/router.go

@@ -1,67 +1,67 @@
 package vision
 
-// Assessment is the model's own confidence in reading an image.
+// Assessment 是模型对自己读图结果的置信度。
 type Assessment string
 
 const (
-	// AssessmentUnknown means the model reported no self-assessment.
+	// AssessmentUnknown 表示模型未给出自评。
 	AssessmentUnknown Assessment = "unknown"
-	// AssessmentGood means the model is confident in its read.
+	// AssessmentGood 表示模型对自己的读图结果有信心。
 	AssessmentGood Assessment = "good"
-	// AssessmentPoor means the model judged its recognition as poor.
+	// AssessmentPoor 表示模型判定自己的识别效果差。
 	AssessmentPoor Assessment = "poor"
 )
 
-// ModelInfo describes the main model's vision capability.
+// ModelInfo 描述主模型的视觉能力。
 type ModelInfo struct {
-	// Name identifies the model.
+	// Name 标识模型。
 	Name string
-	// SupportsVision reports whether the model accepts image input.
+	// SupportsVision 报告模型是否接受图像输入。
 	SupportsVision bool
-	// SelfAssessment is the model's own confidence for the current image.
-	// It drives the layer-2 tool route when SupportsVision is true.
+	// SelfAssessment 是模型对当前图像的自评置信度。
+	// 当 SupportsVision 为真时，它决定是否走第二层工具路由。
 	SelfAssessment Assessment
 }
 
-// DecisionKind is the chosen layered route.
+// DecisionKind 是选定的分层路由。
 type DecisionKind string
 
 const (
-	// KindMain routes the image to the main model with the image in context.
+	// KindMain 把图像连同上下文一起交给主模型。
 	KindMain DecisionKind = "main"
-	// KindVisionTool routes to a dedicated vision tool, returning only the tool
-	// result so the image never occupies main-model context.
+	// KindVisionTool 路由到专用视觉工具，只返回工具
+	// 结果，使图像不占用主模型上下文。
 	KindVisionTool DecisionKind = "vision_tool"
-	// KindOCRTool routes to an OCR tool, returning only the extracted text.
+	// KindOCRTool 路由到 OCR 工具，只返回抽取出的文字。
 	KindOCRTool DecisionKind = "ocr_tool"
-	// KindUnsupported means no route can process the image.
+	// KindUnsupported 表示没有任何路由能处理该图像。
 	KindUnsupported DecisionKind = "unsupported"
 )
 
-// Decision is the outcome of a routing call.
+// Decision 是一次路由调用的结果。
 type Decision struct {
-	// Kind is the chosen route.
+	// Kind 是选定的路由。
 	Kind DecisionKind
-	// Tool names the vision or OCR tool to invoke, set when Kind is a tool route.
+	// Tool 指名要调用的视觉或 OCR 工具，当 Kind 为工具路由时设置。
 	Tool string
-	// Reason is a human-readable explanation for observability and logs.
+	// Reason 是便于可观测与日志的人类可读说明。
 	Reason string
 }
 
-// RouteRequest carries routing hints from the caller on top of the model info.
+// RouteRequest 携带调用方在模型信息之外给出的路由提示。
 type RouteRequest struct {
-	// TextPrimary reports that the user indicated the image is mainly text, so
-	// an OCR tool is preferred over a general vision model.
+	// TextPrimary 表示用户指出图像以文字为主，因此
+	// 优先使用 OCR 工具而非通用视觉模型。
 	TextPrimary bool
-	// MainSelfAssessedPoor is set when the main model has already judged its own
-	// read of the image as poor, requesting a vision/OCR tool route.
+	// MainSelfAssessedPoor 在主模型已自评读图效果
+	// 较差、请求走 vision/OCR 工具路由时置位。
 	MainSelfAssessedPoor bool
 }
 
-// RouterOption configures a Router.
+// RouterOption 配置 Router。
 type RouterOption func(*Router)
 
-// WithVisionTool binds the name of the registered vision-understanding tool.
+// WithVisionTool 绑定已注册的图像理解工具名。
 func WithVisionTool(name string) RouterOption {
 	return func(r *Router) {
 		if name != "" {
@@ -70,7 +70,7 @@ func WithVisionTool(name string) RouterOption {
 	}
 }
 
-// WithOCRTool binds the name of the registered OCR tool.
+// WithOCRTool 绑定已注册的 OCR 工具名。
 func WithOCRTool(name string) RouterOption {
 	return func(r *Router) {
 		if name != "" {
@@ -79,15 +79,15 @@ func WithOCRTool(name string) RouterOption {
 	}
 }
 
-// Router implements the layered vision routing policy. It does no I/O; the
-// caller uses the returned Decision to dispatch the request.
+// Router 实现分层视觉路由策略。它不做任何 I/O；调用方
+// 用返回的 Decision 去派发请求。
 type Router struct {
 	visionTool string
 	ocrTool    string
 }
 
-// NewRouter builds a Router. Unknown (empty) tool names leave the corresponding
-// route unavailable, so the router degrades to KindMain or KindUnsupported.
+// NewRouter 构造 Router。未知（空）的工具名会让对应
+// 路由不可用，于是路由器降级为 KindMain 或 KindUnsupported。
 func NewRouter(opts ...RouterOption) *Router {
 	r := &Router{}
 	for _, o := range opts {
@@ -96,21 +96,21 @@ func NewRouter(opts ...RouterOption) *Router {
 	return r
 }
 
-// Route picks a layered route for an image request given the target model info
-// and caller hints. The order is: the main model directly when it can see and
-// has not self-assessed poorly (layer 1); otherwise a vision or OCR tool whose
-// result replaces the image in context (layers 2 and 3); otherwise
-// KindUnsupported when nothing can process the image.
+// Route 依据目标模型信息与调用方提示，为一次图像请求
+// 选出分层路由。顺序为：主模型能看图且
+// 未自评较差时直接用它（第一层）；否则用能替换
+// 上下文中图像的视觉或 OCR 工具（第二、三层）；再否则
+// 没有任何东西能处理该图像时给出 KindUnsupported。
 func (r *Router) Route(target ModelInfo, req RouteRequest) Decision {
 	poor := target.SelfAssessment == AssessmentPoor || req.MainSelfAssessedPoor
-	// Layer 1: the main model accepts images and is confident, so use it first.
+	// 第一层：主模型接受图像且自信，优先使用它。
 	if target.SupportsVision && !poor {
 		return Decision{
 			Kind:   KindMain,
 			Reason: "main model supports vision and is confident; use it directly",
 		}
 	}
-	// OCR is preferred when the user says the image is mostly text.
+	// 用户说明图像以文字为主时优先 OCR。
 	if req.TextPrimary && r.ocrTool != "" {
 		return Decision{Kind: KindOCRTool, Tool: r.ocrTool, Reason: "image is mainly text; route to OCR"}
 	}
@@ -120,7 +120,7 @@ func (r *Router) Route(target ModelInfo, req RouteRequest) Decision {
 	if r.ocrTool != "" {
 		return Decision{Kind: KindOCRTool, Tool: r.ocrTool, Reason: "route to OCR tool"}
 	}
-	// No tool is bound. A sighted main model remains the only option.
+	// 未绑定任何工具。能看图的主模型仍是唯一选择。
 	if target.SupportsVision {
 		return Decision{Kind: KindMain, Reason: "no vision/OCR tool bound; keep image with main model"}
 	}