docs(comments): 注释中文化 · internal/runtime/memory（31 文件，纯替换）

- 只翻注释/文档字符串：820 增 / 820 删 严格 1:1；剥掉整行注释与行尾注释尾巴后，
  逐文件与 HEAD 比对「代码部分差异 = 0」；裁决/design 编号计数逐项与 HEAD 一致
- 保留可执行 SQL 样例、SQLite 报错原文、pgvector/HNSW/ANN/BLOB 等技术词原文
- 复核：go build 绿 + memory/projectindex/vector 三包测试绿；gofmt 仅剩 2 个既有未格式化文件（改动前即如此，未顺手修）

internal/runtime/memory/projectindex/store.go

@@ -1,23 +1,23 @@
-// Package projectindex implements the project-index hierarchy from
-// DevDocs/design/03-记忆.md §3 ("项目记忆"作用域): a project is indexed as an
-// entry plus description, and its content is split into chapters that can be
-// searched line by line. The three-layer depth is 项目索引 → 项目描述 → 章节内容.
+// projectindex 包实现 DevDocs/design/03-记忆.md §3（「项目记忆」作用域）中的
+// 项目索引层级：一个项目被索引为一条
+// 条目加描述，其内容被切成可逐行检索的章节。
+// 三层深度为 项目索引 → 项目描述 → 章节内容。
 //
-// The two tables model that depth: the project row is the index entry (layer 1)
-// carrying its description (layer 2), and project_chapter holds the chapter
-// content (layer 3). Project memory is readable and writable by every persona
-// (design §3 "人人可读可写", "项目索引各角色可查"), so the store carries no
-// persona/role column and never filters by identity here.
+// 两张表刻画该深度：project 行是指引条目（第 1 层），
+// 携带其描述（第 2 层），project_chapter 保存章节
+// 内容（第 3 层）。项目记忆每个角色都可读写
+// （design §3「人人可读可写」「项目索引各角色可查」），因此存储没有
+// persona/role 列，也不在此按身份过滤。
 //
-// This package is deliberately separate from the vector index
-// (internal/runtime/memory/vector): it does text-based hierarchical indexing of
-// project entries, descriptions, and chapters. Semantic/vector search belongs to
-// the vector package.
+// 本包刻意与向量索引
+// （internal/runtime/memory/vector）分离：它对项目条目、描述与章节
+// 做基于文本的分层索引。语义/向量检索属于
+// 向量包。
 //
-// The store owns its schema: New creates the project and project_chapter tables
-// and the chapter index idempotently. All SQL is parameterized (?), column lists
-// are explicit (no SELECT *), reads take a context.Cancel, and every error is
-// wrapped with %w so callers can use errors.Is against the package sentinels.
+// 存储自己拥有 schema：New 幂等地创建 project 与 project_chapter 表
+// 及章节索引。所有 SQL 参数化（?），列清单
+// 显式列出（无 SELECT *），读取带 context.Cancel，且每个错误都
+// 用 %w 包裹，调用方可用 errors.Is 对包哨兵错误判断。
 package projectindex
 
 import (
@@ -31,56 +31,56 @@ import (
 	"git.yeij.top/AskaEth/Cyrene_v2/internal/logger"
 )
 
-// Sentinels distinguishing projectindex failures. Each is wrapped with %w at the
-// call site so callers can use errors.Is.
+// 区分 projectindex 各类失败的哨兵错误。每个都在
+// 调用点用 %w 包裹，调用方可用 errors.Is 判断。
 var (
-	// ErrProjectNotFound is returned when a project id is blank or does not exist.
+	// ErrProjectNotFound 在项目 id 为空或不存在时返回。
 	ErrProjectNotFound = errors.New("projectindex: project not found")
 
-	// ErrChapterNotFound is returned when a required chapter reference is invalid.
+	// ErrChapterNotFound 在必需的章节引用无效时返回。
 	ErrChapterNotFound = errors.New("projectindex: chapter not found")
 
-	// ErrNilDB is returned when New receives a nil *sql.DB.
+	// ErrNilDB 在 New 收到 nil *sql.DB 时返回。
 	ErrNilDB = errors.New("projectindex: nil db")
 
-	// ErrMissingProject is returned when a required project id is blank.
+	// ErrMissingProject 在必需的 project id 为空时返回。
 	ErrMissingProject = errors.New("projectindex: project_id is required")
 
-	// ErrMissingTitle is returned when a project or chapter title is blank.
+	// ErrMissingTitle 在项目或章节标题为空时返回。
 	ErrMissingTitle = errors.New("projectindex: title is required")
 
-	// ErrMissingContent is returned when a chapter has no content.
+	// ErrMissingContent 在章节没有内容时返回。
 	ErrMissingContent = errors.New("projectindex: content is required")
 
-	// ErrMissingKeyword is returned when Search receives a blank keyword.
+	// ErrMissingKeyword 在 Search 收到空关键词时返回。
 	ErrMissingKeyword = errors.New("projectindex: keyword is required")
 )
 
-// Store is a project-index store backed by a *sql.DB.
+// Store 是基于 *sql.DB 的项目索引存储。
 //
-// It owns its schema: New creates the project / project_chapter tables and the
-// chapter index idempotently. Concurrency is delegated to *sql.DB, which is safe
-// for concurrent use by contract, so Store holds no further lock. Every query is
-// parameterized and reads take a context.Cancel.
+// 它自己拥有 schema：New 幂等地创建 project / project_chapter 表与
+// 章节索引。并发交由 *sql.DB，按约定它可安全
+// 并发使用，因此 Store 不再持锁。每个查询都
+// 参数化，读取带 context.Cancel。
 type Store struct {
 	db  *sql.DB
 	log *slog.Logger
 }
 
-// rowScanner is satisfied by both *sql.Row and *sql.Rows so a single scanProject
-// or scanChapter helper serves both the Get and List paths.
+// rowScanner 同时被 *sql.Row 与 *sql.Rows 满足，因此单个 scanProject
+// 或 scanChapter 辅助函数即可服务 Get 与 List 两条路径。
 type rowScanner interface {
 	Scan(dest ...any) error
 }
 
-// New builds a Store on db, ensuring the schema exists.
+// New 在 db 上构建 Store，确保 schema 存在。
 //
-// db must be a live connection (the migration framework is owned by
-// internal/db). A nil db returns ErrNilDB. log may be nil, in which case a
-// discard logger is used; the active logger is tagged with source
-// "memory/projectindex" so every record is traceable. ctx controls schema
-// creation and must be honored by the caller. Legacy variable-width timestamps
-// are normalized in place (see normalizeTimestamps).
+// db 必须是存活的连接（迁移框架由
+// internal/db 拥有）。nil db 返回 ErrNilDB。log 可为 nil，此时
+// 使用丢弃型 logger；实际使用的 logger 带 source
+// "memory/projectindex" 标签，因此每条记录都可追溯。ctx 控制 schema
+// 创建，调用方必须遵守。旧的变宽时间戳
+// 就地规范化（见 normalizeTimestamps）。
 func New(ctx context.Context, db *sql.DB, log *slog.Logger) (*Store, error) {
 	if db == nil {
 		return nil, ErrNilDB
@@ -101,7 +101,7 @@ func New(ctx context.Context, db *sql.DB, log *slog.Logger) (*Store, error) {
 	return &Store{db: db, log: log}, nil
 }
 
-// discardLogger returns log if non-nil, otherwise a logger that writes nowhere.
+// discardLogger 在 log 非 nil 时返回 log，否则返回一个不写任何地方的 logger。
 func discardLogger(log *slog.Logger) *slog.Logger {
 	if log != nil {
 		return log
@@ -109,12 +109,12 @@ func discardLogger(log *slog.Logger) *slog.Logger {
 	return slog.New(slog.NewTextHandler(io.Discard, nil))
 }
 
-// ListProjects returns every project index entry in insertion order (created_at
-// ASC, rowid ASC) — rowid breaks created_at ties so projects written within the
-// same clock tick keep their insertion order. An empty (non-nil) slice is
-// returned when there are none, so callers can range over it unconditionally. A
-// read error is wrapped with %w so callers can use errors.Is against the package
-// sentinels.
+// ListProjects 按插入顺序（created_at ASC、rowid ASC）返回每个
+// 项目索引条目 —— rowid 打破 created_at 并列，使同一时钟刻内写入的项目
+// 保持其插入顺序。没有条目时返回空的
+// （非 nil）切片，调用方可以无条件 range。读
+// 错误用 %w 包裹，调用方可用 errors.Is 对包
+// 哨兵错误判断。
 func (s *Store) ListProjects(ctx context.Context) ([]Project, error) {
 	rows, err := s.db.QueryContext(ctx, `SELECT id, title, desc, created_at, updated_at
 		FROM project ORDER BY created_at ASC, rowid ASC`)
@@ -137,9 +137,9 @@ func (s *Store) ListProjects(ctx context.Context) ([]Project, error) {
 	return projects, nil
 }
 
-// Schema DDL, applied idempotently by New. The two tables model the three-layer
-// hierarchy: the project row is the index entry (layer 1) plus its description
-// (layer 2), and project_chapter holds the chapter content (layer 3).
+// schema DDL，由 New 幂等施加。两张表刻画三层
+// 层级：project 行是指引条目（第 1 层）加其描述
+// （第 2 层），project_chapter 保存章节内容（第 3 层）。
 const createProjectTable = `
 CREATE TABLE IF NOT EXISTS project (
     id         TEXT PRIMARY KEY,