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_trace.go

@@ -7,12 +7,12 @@ import (
 	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/trace"
 )
 
-// defaultTraceBufCap is how many completed spans the ring buffer holds before the
-// oldest is evicted. Compile-time constant.
+// defaultTraceBufCap 是环形缓冲在逐出最旧 span 之前持有的已
+// 完成 span 数。编译期常量。
 const defaultTraceBufCap = 512
 
-// AdminTraceSpan is the camelCase wire shape of one traced span. It decouples the
-// frontend from the trace package's snake_case SpanRecord.
+// AdminTraceSpan 是一个已追踪 span 的驼峰式线上结构。它把
+// 前端与 trace 包蛇形命名的 SpanRecord 解耦。
 type AdminTraceSpan struct {
 	ID         string         `json:"id"`
 	ParentID   string         `json:"parentId,omitempty"`
@@ -26,9 +26,9 @@ type AdminTraceSpan struct {
 	Events     []trace.Event  `json:"events,omitempty"`
 }
 
-// RingBuffer is a concurrency-safe bounded buffer of completed trace spans. The
-// oldest span is evicted when the buffer is full, so the admin panel always sees
-// the most recent work without unbounded growth.
+// RingBuffer 是已完成的 trace span 的并发安全有界缓冲。缓冲
+// 满时逐出最旧 span，因此管理面板总能看到
+// 最近的工作而不会无界增长。
 type RingBuffer struct {
 	mu   sync.RWMutex
 	buf  []trace.SpanRecord
@@ -37,7 +37,7 @@ type RingBuffer struct {
 	cap  int
 }
 
-// newRingBuffer builds a ring buffer holding up to cap spans (default when cap<=0).
+// newRingBuffer 构建至多容纳 cap 个 span 的环形缓冲（cap<=0 时用默认值）。
 func newRingBuffer(cap int) *RingBuffer {
 	if cap <= 0 {
 		cap = defaultTraceBufCap
@@ -45,7 +45,7 @@ func newRingBuffer(cap int) *RingBuffer {
 	return &RingBuffer{buf: make([]trace.SpanRecord, cap), cap: cap}
 }
 
-// Append stores rec, evicting the oldest when the buffer is full.
+// Append 存储 rec，缓冲满时逐出最旧的。
 func (r *RingBuffer) Append(rec trace.SpanRecord) {
 	r.mu.Lock()
 	defer r.mu.Unlock()
@@ -56,8 +56,8 @@ func (r *RingBuffer) Append(rec trace.SpanRecord) {
 	}
 }
 
-// Snapshot returns up to n most-recent spans, newest first. A non-positive n
-// selects defaultObsLimit; n is clamped to maxObsLimit.
+// Snapshot 返回至多 n 条最近 span，最新优先。非正的 n
+// 选用 defaultObsLimit；n 被夹取到 maxObsLimit。
 func (r *RingBuffer) Snapshot(n int) []trace.SpanRecord {
 	if n <= 0 {
 		n = defaultObsLimit
@@ -82,11 +82,11 @@ func (r *RingBuffer) Snapshot(n int) []trace.SpanRecord {
 	return out
 }
 
-// traceSink adapts a *RingBuffer to trace.Writer so a completed span is appended
-// to the gateway's trace buffer.
+// traceSink 把 *RingBuffer 适配为 trace.Writer，使已完成的 span 被
+// 追加进网关的 trace 缓冲。
 type traceSink struct{ b *RingBuffer }
 
-// WriteSpan appends rec to the ring buffer.
+// WriteSpan 把 rec 追加进环形缓冲。
 func (s traceSink) WriteSpan(rec trace.SpanRecord) error {
 	if s.b == nil {
 		return nil
@@ -95,16 +95,16 @@ func (s traceSink) WriteSpan(rec trace.SpanRecord) error {
 	return nil
 }
 
-// MultiTraceWriter fans a completed span out to several trace.Writers, so a tracer
-// can record to both the gateway's ring buffer and a JSONL file in one pass. A nil
-// Writer is skipped. It is the composition-root helper the main session uses to
-// route the loop tracer's output into the gateway without dropping stderr.
+// MultiTraceWriter 把已完成的 span 扇出到多个 trace.Writer，使一个
+// tracer 能一趟同时记录到网关的环形缓冲与一个 JSONL 文件。nil 的
+// Writer 被跳过。它是主会话用来把 loop tracer 的输出引入
+// 网关而不丢掉 stderr 的组合根辅助件。
 type MultiTraceWriter struct {
-	// Writers are the sinks a span is written to. A nil Writer is skipped.
+	// Writers 是 span 被写入的汇聚点。nil 的 Writer 被跳过。
 	Writers []trace.Writer
 }
 
-// WriteSpan writes rec to every configured Writer.
+// WriteSpan 把 rec 写入每一个已配置的 Writer。
 func (m MultiTraceWriter) WriteSpan(rec trace.SpanRecord) error {
 	for _, w := range m.Writers {
 		if w == nil {
@@ -117,7 +117,7 @@ func (m MultiTraceWriter) WriteSpan(rec trace.SpanRecord) error {
 	return nil
 }
 
-// adminSpanOf maps a trace.SpanRecord to the camelCase admin wire shape.
+// adminSpanOf 把 trace.SpanRecord 映射为驼峰式管理线上结构。
 func adminSpanOf(rec trace.SpanRecord) AdminTraceSpan {
 	sp := AdminTraceSpan{
 		ID:         rec.ID,