docs(comments): 注释中文化 · internal/runtime/model + internal/services/backthink（54 文件，纯替换）

- 只翻注释/文档字符串：`go/scanner` 剥注释后按 token 序列+literal 逐 token 比对，**54/54 文件 SAME**；
  改动文件总行数与 HEAD 漂移 = 0（严格 1:1，无合并/拆行）
- 裁决编号与 design 节号逐字保留（03.4.1/03.4.2/03.4.3/14.4.1/14.4.5/07.4.2-4、design/04 §3.1/§3.2 等）；
  `chat_template_kwargs` / `enable_thinking` / `reasoning_effort` / `thinking:{type}` 字段名与形状说明未动
- 存疑译法（已登记）：`persona` 在叙事语境用「角色」、标识符语境保留 `persona`（仓库既有模块本身混用）；
  `rung`→「级」；`provider` 存在「提供商/提供者」两种落笔（可按需一键统一）
- 复核：build/vet 绿 + 两包测试绿；gofmt 干净；残留英文注释 0 条
- 既有存量（未修，只报告）：`model/anthropic_test.go` 612 行 >500；`applyAnthropicEvent` 115 行 >80

internal/runtime/model/anthropic_reasoning.go

@@ -5,27 +5,27 @@ import (
 	"strings"
 )
 
-// Anthropic extended-thinking protocol bounds (design/04 §3.2).
+// Anthropic 扩展思考协议的边界（design/04 §3.2）。
 const (
-	// anthropicMinThinkingBudget is the smallest budget_tokens the Messages API
-	// accepts for thinking.type=enabled; anything below it is rejected with a
-	// 400, so a lower non-zero budget is raised and reported rather than sent.
+	// anthropicMinThinkingBudget 是 Messages API 在 thinking.type=enabled 时
+	// 接受的最小 budget_tokens；低于它会被 400 拒绝，
+	// 因此更低但非零的预算会被抬高并上报，而不是照发。
 	anthropicMinThinkingBudget = 1024
-	// anthropicDefaultThinkingBudget is used when thinking is switched on without
-	// an explicit budget.
+	// anthropicDefaultThinkingBudget 在开启思考但未给
+	// 显式预算时使用。
 	anthropicDefaultThinkingBudget = 4096
-	// anthropicThinkingBodyReserve is the body room kept on top of the thinking
-	// budget: max_tokens is shared by thinking and the visible answer, so the
-	// budget must never be allowed to consume it all (design/04 §3.2 red line:
+	// anthropicThinkingBodyReserve 是在思考预算之上留给正文的空间：
+	// max_tokens 由思考与可见答案共享，所以
+	// 预算绝不允许把它全部吃光（design/04 §3.2 红线：
 	// "预算与正文不得互相吃光").
 	anthropicThinkingBodyReserve = 2048
 )
 
-// deepSeekAnthropicEndpoint reports whether an Anthropic-protocol request is
-// really served by DeepSeek's /anthropic endpoint. The base URL is checked first
-// because the endpoint — not the model name — decides whether budget_tokens is
-// honoured, and a DeepSeek endpoint is commonly configured with a non-DeepSeek
-// model name (the service silently maps unknown names onto deepseek-flash).
+// deepSeekAnthropicEndpoint 报告一次 Anthropic 协议请求是否
+// 真的由 DeepSeek 的 /anthropic 端点服务。先检查 base URL，
+// 因为是端点——而不是模型名——决定 budget_tokens 是否
+// 被尊重，而 DeepSeek 端点常常配着一个非 DeepSeek 的
+// 模型名（该服务会把未知名称静默映射到 deepseek-flash）。
 func deepSeekAnthropicEndpoint(model, baseURL string) bool {
 	if strings.Contains(strings.ToLower(baseURL), "deepseek") {
 		return true
@@ -33,16 +33,16 @@ func deepSeekAnthropicEndpoint(model, baseURL string) bool {
 	return reasoningVendorFor(model, baseURL) == vendorDeepSeek
 }
 
-// anthropicThinkingFor resolves the extended-thinking directive together with the
-// max_tokens it requires. It returns the (possibly raised) max_tokens and the
-// wire block; a nil block means "do not send thinking" (no directive, or an
-// explicit off). Because max_tokens is shared by thinking and the visible answer,
-// the returned budget always leaves anthropicThinkingBodyReserve for the body,
-// and a request whose budget would eat the answer raises max_tokens instead — the
-// adjustment is logged so it is never a silent rewrite.
+// anthropicThinkingFor 解出扩展思考指令以及它所需的
+// max_tokens。它返回（可能已被抬高的）max_tokens 与
+// 线格式块；块为 nil 表示「不发送思考」（无指令，或
+// 显式关闭）。由于 max_tokens 由思考与可见答案共享，
+// 返回的预算总会为正文留下 anthropicThinkingBodyReserve，
+// 而预算会吃光答案的请求则改为抬高 max_tokens——该
+// 调整会被记录，因此绝不是一次静默改写。
 //
-// This is the Anthropic endpoint's rule only. A DeepSeek /anthropic endpoint
-// ignores budget_tokens, so it must not go through here (design/04 §3.2 fact 6).
+// 这条规则只适用于 Anthropic 端点。DeepSeek 的 /anthropic 端点
+// 会忽略 budget_tokens，所以它绝不能走这里（design/04 §3.2 事实 6）。
 func anthropicThinkingFor(th *Thinking, maxTokens int, log *slog.Logger) (int, *anthropicThinking) {
 	if th == nil || (th.Enable != nil && !*th.Enable) {
 		return maxTokens, nil
@@ -67,12 +67,12 @@ func anthropicThinkingFor(th *Thinking, maxTokens int, log *slog.Logger) (int, *
 	return maxTokens, &anthropicThinking{Type: anthropicThinkingTypeEnabled, BudgetTokens: budget}
 }
 
-// anthropicDeepSeekReasoning resolves the reasoning knobs for a DeepSeek
-// /anthropic request. Two differences from the Anthropic endpoint drive it: that
-// endpoint ignores budget_tokens, so max_tokens is left untouched (raising it
-// would misreport the budget the provider actually applies), and strength is
-// controlled by output_config.effort, which has no "none" value — there the "off"
-// intent is carried by the thinking switch itself (design/04 §3.2 facts 2 and 6).
+// anthropicDeepSeekReasoning 解出 DeepSeek /anthropic 请求的
+// 推理旋钮。与 Anthropic 端点的两点差异决定了它：该
+// 端点忽略 budget_tokens，所以 max_tokens 保持不动（抬高它
+// 会错误反映提供商实际采用的预算），而强度由
+// output_config.effort 控制，它没有 "none" 取值——在那里「关闭」
+// 意图由 thinking 开关自身承载（design/04 §3.2 事实 2 与 6）。
 func anthropicDeepSeekReasoning(log *slog.Logger, model string, th *Thinking, effort string) (*anthropicThinking, *anthropicOutputConfig) {
 	var block *anthropicThinking
 	if th != nil {
@@ -118,9 +118,9 @@ func anthropicDeepSeekReasoning(log *slog.Logger, model string, th *Thinking, ef
 	return block, &anthropicOutputConfig{Effort: tier}
 }
 
-// anthropicThinkingOn reports the effective thinking state of a resolved DeepSeek
-// /anthropic request: an omitted switch leaves the provider default in place, and
-// DeepSeek's default is enabled.
+// anthropicThinkingOn 报告一个已解出的 DeepSeek /anthropic 请求的
+// 实际思考状态：省略开关会保留提供商默认值，而
+// DeepSeek 的默认是开启。
 func anthropicThinkingOn(th *anthropicThinking) bool {
 	return th == nil || th.Type != thinkingTypeDisabled
 }