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/persona_provider_test.go

@@ -89,10 +89,10 @@ func TestRuntimeLLM_PersonaProviderSelectsTheOtherProtocol(t *testing.T) {
 	}
 }
 
-// TestRuntimeLLM_PersonaProviderAppliesToStreamingToo asserts the streaming path
-// (the main chat path: loop.streamStep → adapter.ChatStream) resolves the same
-// persona chain as the non-streaming one — a persona route that only worked on
-// one of the two paths would be a silent half-fix.
+// TestRuntimeLLM_PersonaProviderAppliesToStreamingToo 断言流式路径
+// （主聊天路径：loop.streamStep → adapter.ChatStream）解析出与非流式
+// 相同的那条 persona 链——只在两条路径之一生效的 persona
+// 路由只能算一次静默的半修。
 func TestRuntimeLLM_PersonaProviderAppliesToStreamingToo(t *testing.T) {
 	t.Parallel()
 	anthropicCh := make(chan anthropicCaptured, 1)
@@ -123,9 +123,9 @@ func TestRuntimeLLM_PersonaProviderAppliesToStreamingToo(t *testing.T) {
 	}
 }
 
-// TestPersonaStack_StampsPersonaOnEveryRequest pins the carrier that lets a
-// per-persona agent wire the route without the loop handing over its ctx: the
-// scoped adapter view stamps PersonaID and routes the model by that persona.
+// TestPersonaStack_StampsPersonaOnEveryRequest 钉住那个载体：它让
+// 按 persona 的 agent 能在 loop 不交出自身 ctx 的情况下接好路由，
+// 即作用域化的适配器视图打上 PersonaID 并按该 persona 路由模型。
 func TestPersonaStack_StampsPersonaOnEveryRequest(t *testing.T) {
 	t.Parallel()
 	f := newPersonaProviderFixture(t, nil)
@@ -151,8 +151,8 @@ func TestPersonaStack_StampsPersonaOnEveryRequest(t *testing.T) {
 	}
 }
 
-// TestPersonaStack_BlankPersonaKeepsDefaultRoute asserts an unbound view is a
-// pass-through: an empty persona must not turn into a binding of its own.
+// TestPersonaStack_BlankPersonaKeepsDefaultRoute 断言未绑定的视图是
+// 直通：空的 persona 不得变成它自己的一个绑定。
 func TestPersonaStack_BlankPersonaKeepsDefaultRoute(t *testing.T) {
 	t.Parallel()
 	f := newPersonaProviderFixture(t, nil)
@@ -177,10 +177,10 @@ func TestPersonaStack_BlankPersonaKeepsDefaultRoute(t *testing.T) {
 	}
 }
 
-// TestRuntimeLLM_PersonaProviderWithoutOwnModelKeepsDefaultChain covers the
-// half-declared config: a personaProviders entry alone says nothing about which
-// model to send, so switching protocol would push the group's default model name
-// to another vendor's endpoint. The default chain is kept and the reason logged.
+// TestRuntimeLLM_PersonaProviderWithoutOwnModelKeepsDefaultChain 覆盖
+// 半声明的配置：只有一条 personaProviders 条目并不能说明该发
+// 哪个模型，所以切换协议会把组的默认模型名推到
+// 另一厂商的端点。此时保留默认链并记录原因。
 func TestRuntimeLLM_PersonaProviderWithoutOwnModelKeepsDefaultChain(t *testing.T) {
 	t.Parallel()
 	f := newPersonaProviderFixture(t, func(g *runtimeconfig.Group) {
@@ -200,9 +200,9 @@ func TestRuntimeLLM_PersonaProviderWithoutOwnModelKeepsDefaultChain(t *testing.T
 	}
 }
 
-// TestRuntimeLLM_PersonaProviderWithoutAGroupKeepsDefaultChain covers a declared
-// protocol that models.json has no group for: the persona keeps the default chain
-// instead of failing the turn, and the skip is reported.
+// TestRuntimeLLM_PersonaProviderWithoutAGroupKeepsDefaultChain 覆盖已声明
+// 但 models.json 没有对应组的协议：该 persona 保留默认链
+// 而不是让回合失败，并上报这次跳过。
 func TestRuntimeLLM_PersonaProviderWithoutAGroupKeepsDefaultChain(t *testing.T) {
 	t.Parallel()
 	openaiCh := make(chan capturedRequest, 1)
@@ -231,9 +231,9 @@ func TestRuntimeLLM_PersonaProviderWithoutAGroupKeepsDefaultChain(t *testing.T)
 	}
 }
 
-// TestRuntimeLLM_PersonaProviderSameProtocolReusesDefaultChain asserts a persona
-// naming the active group's own protocol builds no second chain: the default one
-// already speaks it, and the per-persona model name reaches it via the router.
+// TestRuntimeLLM_PersonaProviderSameProtocolReusesDefaultChain 断言声明了
+// 生效组自身协议的 persona 不会构建第二条链：默认链
+// 本就说那个协议，按 persona 的模型名经路由器到达它。
 func TestRuntimeLLM_PersonaProviderSameProtocolReusesDefaultChain(t *testing.T) {
 	t.Parallel()
 	f := newPersonaProviderFixture(t, func(g *runtimeconfig.Group) {