docs(gateway): gateway 剩余文件注释改中文（逐行 1:1，代码零字节改动）

主人 2026-10-03 拍板「注释一律中文」；gateway 至此整包注释中文化完成（本会话共 3 批：
已推库 16 个文件 + 本批剩余文件）。
校验：机械校验（非注释改动行）= 空；剥注释后代码文本逐行比对全等（不一致文件数 0）；
全树 go test ./... 58 包 ok / 0 FAIL；交叉编译绿。

internal/services/gateway/observability_audit.go

@@ -9,7 +9,7 @@ import (
 	"time"
 )
 
-// AuditRecord is one persisted admin audit entry (who/what/when/result).
+// AuditRecord 是一条持久化的管理审计条目（who/what/when/result）。
 type AuditRecord struct {
 	ID     int64  `json:"id"`
 	Who    string `json:"who"`
@@ -18,33 +18,33 @@ type AuditRecord struct {
 	Result string `json:"result"`
 }
 
-// AuditStore persists the admin audit trail. Implementations must be safe for
-// concurrent use. *SQLiteAuditStore is the production implementation (wired by the
-// composition root over a.db); when none is injected the gateway falls back to an
-// in-memory store so the endpoint always returns data.
+// AuditStore 持久化管理审计链。实现必须对
+// 并发使用安全。*SQLiteAuditStore 是生产实现（由
+// 组合根接到 a.db 上）；未注入任何实现时网关回退到
+// 内存存储，因此端点总能返回数据。
 type AuditStore interface {
-	// Append persists one audit entry at ts.
+	// Append 在 ts 持久化一条审计条目。
 	Append(ctx context.Context, who, what, result string, ts time.Time) error
-	// List returns at most limit most-recent entries, newest first. A non-positive
-	// limit selects the default.
+	// List 返回至多 limit 条最近条目，最新优先。非正的
+	// limit 选用默认值。
 	List(ctx context.Context, limit int) ([]AuditRecord, error)
 }
 
-// memoryAuditStore is the nil-injection fallback: it holds the audit trail in
-// process memory so the admin endpoint works before the composition root injects a
-// SQLite store. It is concurrency-safe.
+// memoryAuditStore 是未注入时的回退：它把审计链放在
+// 进程内存中，使管理端点在组合根注入 SQLite 存储
+// 之前也能工作。它对并发安全。
 type memoryAuditStore struct {
 	mu      sync.Mutex
 	records []AuditRecord
 	seq     int64
 }
 
-// newMemoryAuditStore builds an empty in-memory audit store.
+// newMemoryAuditStore 构建一个空的内存审计存储。
 func newMemoryAuditStore() *memoryAuditStore {
 	return &memoryAuditStore{records: make([]AuditRecord, 0, 64)}
 }
 
-// Append stores one entry with a monotonically increasing id.
+// Append 用单调递增的 id 存一条条目。
 func (m *memoryAuditStore) Append(ctx context.Context, who, what, result string, ts time.Time) error {
 	if err := ctx.Err(); err != nil {
 		return err
@@ -58,7 +58,7 @@ func (m *memoryAuditStore) Append(ctx context.Context, who, what, result string,
 	return nil
 }
 
-// List returns the most recent entries, newest first.
+// List 返回最近的条目，最新优先。
 func (m *memoryAuditStore) List(ctx context.Context, limit int) ([]AuditRecord, error) {
 	if err := ctx.Err(); err != nil {
 		return nil, err
@@ -84,9 +84,9 @@ func (m *memoryAuditStore) List(ctx context.Context, limit int) ([]AuditRecord,
 	return out, nil
 }
 
-// audit DDL for a self-contained SQLite store (no migration bookkeeping), the
-// same pattern channel/session and backthink use. recorded_at is the UTC RFC3339
-// wall-clock of the audited action.
+// 自包含 SQLite 存储的审计 DDL（无需迁移记账），与
+// channel/session 与 backthink 所用模式相同。recorded_at 是被审计
+// 动作的 UTC RFC3339 墙钟时间。
 const (
 	createAuditSQL = `
 CREATE TABLE IF NOT EXISTS audit_logs (
@@ -102,16 +102,16 @@ CREATE TABLE IF NOT EXISTS audit_logs (
 	selectAuditSQL      = `SELECT id, who, what, result, recorded_at FROM audit_logs ORDER BY id DESC LIMIT ?`
 )
 
-// SQLiteAuditStore persists the admin audit trail in SQLite. It is safe for
-// concurrent use by virtue of the underlying *sql.DB.
+// SQLiteAuditStore 把管理审计链持久化在 SQLite 中。凭借底层的
+// *sql.DB，它对并发使用安全。
 type SQLiteAuditStore struct {
 	db  *sql.DB
 	log *slog.Logger
 }
 
-// NewSQLiteAuditStore builds a SQLite-backed audit store over db, guaranteeing the
-// audit_logs table and index exist. It returns an error when db is nil or the DDL
-// fails. The composition root wires this over the primary *sql.DB (a.db).
+// NewSQLiteAuditStore 在 db 上构建 SQLite 审计存储，保证
+// audit_logs 表与索引存在。db 为 nil 或 DDL 失败时
+// 返回错误。组合根把它接到主 *sql.DB（a.db）上。
 func NewSQLiteAuditStore(ctx context.Context, db *sql.DB, log *slog.Logger) (*SQLiteAuditStore, error) {
 	if db == nil {
 		return nil, fmt.Errorf("gateway: audit store: nil database")
@@ -125,7 +125,7 @@ func NewSQLiteAuditStore(ctx context.Context, db *sql.DB, log *slog.Logger) (*SQ
 	return &SQLiteAuditStore{db: db, log: sourcedLog(log)}, nil
 }
 
-// Append persists one audit entry at ts.
+// Append 在 ts 持久化一条审计条目。
 func (s *SQLiteAuditStore) Append(ctx context.Context, who, what, result string, ts time.Time) error {
 	if _, err := s.db.ExecContext(ctx, insertAuditSQL, who, what, result, ts.UTC().Format(time.RFC3339Nano)); err != nil {
 		return fmt.Errorf("gateway: insert audit: %w", err)
@@ -133,7 +133,7 @@ func (s *SQLiteAuditStore) Append(ctx context.Context, who, what, result string,
 	return nil
 }
 
-// List returns the most recent entries, newest first.
+// List 返回最近的条目，最新优先。
 func (s *SQLiteAuditStore) List(ctx context.Context, limit int) ([]AuditRecord, error) {
 	if limit <= 0 {
 		limit = defaultObsLimit