docs(comments): 注释中文化 · internal/runtime/history（15 文件，纯替换）

- 只翻注释/文档字符串：剥离注释后代码行逐字节不变（机械校验只剩 4 条行尾注释的翻译，代码前缀全等）
- 交叉引用（design/16 §4.6、D4/B3、0010 迁移文件名）逐字保留
- 保留未译技术词：DDL/rowid/LIKE/LEFT JOIN/DTO/rune/WS/actor 及全部标识符与表名
- 顺带副作用：store.go、session_persona_test.go 由注释文字改变而变得 gofmt 干净（未运行 gofmt -w）

internal/runtime/history/session_persona.go

@@ -9,22 +9,20 @@ import (
 	"time"
 )
 
-// This file owns the per-session role binding (DevDocs/design/22 多角色并存 +
-// 按会话选角 §2/§4.1). A session's role is the single source of truth for "which
-// role answers in this conversation": the loop resolves the system prompt, the
-// memory scope, the emotion machine and the thinking budget from it. The value
-// is display/scope metadata only — identity and permissions are still decided by
-// the channel actor metadata (project red line).
+// 本文件负责每会话的角色绑定（DevDocs/design/22 多角色并存 +
+// 按会话选角 §2/§4.1）。一个会话的角色是「这个对话里由哪个角色应答」的唯一
+// 事实来源：循环据此解析系统提示词、记忆作用域、情绪机与思考预算。该值只是
+// 展示/作用域元数据 —— 身份与权限仍由渠道 actor 元数据决定（项目红线）。
 //
-// '' means "inherit the current global default role", so it is both the column
-// default and a legal explicit value: setting it clears an explicit binding and
-// lets the session follow a default-role change again (design/22 §7-6).
+// 空意味着「继承当前全局默认角色」，因此它既是列默认值，也是一个合法的显式
+// 取值：把它设为空即清除显式绑定，让会话重新跟随默认角色变更
+// （design/22 §7-6）。
 
-// NewSubSessionFor creates a sub session bound to personaID and returns its id
-// (MainSessionID:uuid). A blank personaID binds no explicit role, so the session
-// inherits the global default — the same behavior as NewSubSession. ownerID is
-// accepted for symmetry with NewSubSession (the Web owner is identified by JWT,
-// not stored per session); it is logged at debug and not persisted.
+// NewSubSessionFor 创建绑定到 personaID 的子会话并返回其 id
+// （MainSessionID:uuid）。personaID 为空则不绑定任何显式角色，会话因此继承
+// 全局默认 —— 与 NewSubSession 行为相同。ownerID 为与 NewSubSession 对称而
+// 接受（Web 主人由 JWT 识别，不按会话存储）；它只以 debug 级别记日志，不被
+// 持久化。
 func (s *Store) NewSubSessionFor(ctx context.Context, ownerID, personaID string) (string, error) {
 	id, err := newID()
 	if err != nil {
@@ -42,11 +40,10 @@ func (s *Store) NewSubSessionFor(ctx context.Context, ownerID, personaID string)
 	return sessionID, nil
 }
 
-// SetSessionPersona binds (or clears, when personaID is blank) a session's role.
-// Both the fixed main session and sub sessions may be retargeted: the binding is
-// scope metadata, not identity. An unknown id returns ErrSessionNotFound. It
-// never touches the conversation: the stored messages keep the role that spoke
-// them (design/22 §7-5), and the next turn simply resolves the new role.
+// SetSessionPersona 绑定（或在 personaID 为空时清除）一个会话的角色。固定主
+// 会话与子会话都可被改绑：该绑定是作用域元数据，不是身份。未知 id 返回
+// ErrSessionNotFound。它绝不触碰对话：已存消息保留说出它们的那个角色
+// （design/22 §7-5），下一个回合只是解析新角色。
 func (s *Store) SetSessionPersona(ctx context.Context, sessionID, personaID string) error {
 	res, err := s.db.ExecContext(ctx, `UPDATE chat_sessions SET persona_id = ? WHERE id = ?`,
 		strings.TrimSpace(personaID), sessionID)
@@ -63,11 +60,9 @@ func (s *Store) SetSessionPersona(ctx context.Context, sessionID, personaID stri
 	return nil
 }
 
-// SessionPersona returns the role bound to sessionID, or "" when the session
-// inherits the global default. An unknown id returns ErrSessionNotFound so a
-// caller can tell "no explicit role" (a real session, empty binding) from "no
-// such session"; a caller that only needs the effective role treats both as
-// "use the default".
+// SessionPersona 返回绑定到 sessionID 的角色，会话继承全局默认时返回空。未知
+// id 返回 ErrSessionNotFound，使调用方能区分「没有显式角色」（真实会话、绑定
+// 为空）与「没有这个会话」；只需要有效角色的调用方把两者都当作「用默认」。
 func (s *Store) SessionPersona(ctx context.Context, sessionID string) (string, error) {
 	var personaID string
 	err := s.db.QueryRowContext(ctx, `SELECT persona_id FROM chat_sessions WHERE id = ?`, sessionID).Scan(&personaID)