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_metrics.go

@@ -8,17 +8,17 @@ import (
 	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/trace"
 )
 
-// Metrics collector tuning. Compile-time constants.
+// 指标收集器调参。编译期常量。
 const (
-	// metricsWindow bounds how long request timestamps are retained for QPS.
+	// metricsWindow 限定请求时间戳为 QPS 保留多久。
 	metricsWindow = 2 * time.Second
-	// metricsQPSSpan is the sliding window over which QPS is measured.
+	// metricsQPSSpan 是测量 QPS 的滑动窗口。
 	metricsQPSSpan = time.Second
 )
 
-// AdminMetrics is the wire shape of GET /api/v1/admin/observability/metrics.
-// LLM/Token cost is deliberately absent: the gateway does not track token usage or
-// spend, and a fabricated number would violate the "不伪造指标" red line.
+// AdminMetrics 是 GET /api/v1/admin/observability/metrics 的线上结构。
+// LLM/Token 成本刻意缺位：网关不跟踪 token 用量或
+// 花费，编造一个数字会违反「不伪造指标」红线。
 type AdminMetrics struct {
 	TotalRequests  int64            `json:"totalRequests"`
 	QPS            float64          `json:"qps"`
@@ -31,8 +31,8 @@ type AdminMetrics struct {
 	SubagentEvents int64            `json:"subagentEvents"`
 }
 
-// MetricsCollector accumulates request metrics and derived counters for the admin
-// observability panel. It is concurrency-safe.
+// MetricsCollector 为管理可观测面板累积请求指标与派生
+// 计数器。它对并发安全。
 type MetricsCollector struct {
 	mu        sync.Mutex
 	total     int64
@@ -46,7 +46,7 @@ type MetricsCollector struct {
 	subagent  int64
 }
 
-// newMetricsCollector builds an empty metrics collector.
+// newMetricsCollector 构建一个空指标收集器。
 func newMetricsCollector() *MetricsCollector {
 	return &MetricsCollector{
 		perMethod: make(map[string]int64),
@@ -55,7 +55,7 @@ func newMetricsCollector() *MetricsCollector {
 	}
 }
 
-// Record counts one request with the given method, path, status and duration.
+// Record 用给定的 method、path、status 与 duration 计一次请求。
 func (m *MetricsCollector) Record(method, path string, status int, durMs int64) {
 	m.mu.Lock()
 	defer m.mu.Unlock()
@@ -72,8 +72,8 @@ func (m *MetricsCollector) Record(method, path string, status int, durMs int64)
 	m.prune(now)
 }
 
-// Observe increments the LLM/subagent counters when a span of that kind is
-// recorded. It is called by ObserveSpan so the counters reflect real work.
+// Observe 在记录到该类 span 时递增 LLM/子代理计数器。
+// 它由 ObserveSpan 调用，使计数器反映真实工作。
 func (m *MetricsCollector) Observe(rec trace.SpanRecord) {
 	m.mu.Lock()
 	defer m.mu.Unlock()
@@ -85,8 +85,8 @@ func (m *MetricsCollector) Observe(rec trace.SpanRecord) {
 	}
 }
 
-// prune drops request times older than metricsWindow so recent stays small. The
-// caller must hold m.mu.
+// prune 丢弃早于 metricsWindow 的请求时间，使 recent 保持小。
+// 调用方必须持有 m.mu。
 func (m *MetricsCollector) prune(now time.Time) {
 	min := now.Add(-metricsWindow)
 	i := 0
@@ -98,15 +98,15 @@ func (m *MetricsCollector) prune(now time.Time) {
 	}
 }
 
-// Snapshot returns a point-in-time copy of the metrics. qps counts the requests
-// started within metricsQPSSpan of now.
+// Snapshot 返回指标的时间点副本。qps 统计在 now 的
+// metricsQPSSpan 之内开始的请求。
 //
-// Every map in the result is a fresh copy, never the collector's own: the caller
-// serializes the value AFTER this lock is released (the admin handler JSON-encodes
-// it), so returning the live maps would let a concurrent Record mutate a map while
-// the encoder iterates it — the Go runtime answers that with an unrecoverable
-// fatal "concurrent map iteration and map write" that takes the whole process
-// down (the 2026-10-03 21:00:28 crash on GET /api/v1/admin/observability/metrics).
+// 结果中的每个 map 都是全新副本，绝不是收集器自己的：调用方
+// 在本锁释放之后才序列化该值（管理 handler 对它做 JSON
+// 编码），因此返回活 map 会让并发的 Record 在编码器
+// 遍历它时改动该 map —— Go 运行时对此的回答是不可恢复的
+// 致命错误 "concurrent map iteration and map write"，它会让整个进程
+// 倒下（2026-10-03 21:00:28 在 GET /api/v1/admin/observability/metrics 上的崩溃）。
 func (m *MetricsCollector) Snapshot(now time.Time) AdminMetrics {
 	m.mu.Lock()
 	defer m.mu.Unlock()
@@ -133,9 +133,9 @@ func (m *MetricsCollector) Snapshot(now time.Time) AdminMetrics {
 	}
 }
 
-// copyCounts returns a detached copy of a string-keyed counter map, so the
-// snapshot can be encoded after the collector's lock is released. The caller must
-// hold m.mu while copying (the copy iterates the live map).
+// copyCounts 返回字符串键计数器 map 的脱离副本，使
+// 快照能在收集器锁释放后编码。调用方在复制时
+// 必须持有 m.mu（复制会遍历活 map）。
 func copyCounts(src map[string]int64) map[string]int64 {
 	out := make(map[string]int64, len(src))
 	for k, v := range src {
@@ -144,8 +144,8 @@ func copyCounts(src map[string]int64) map[string]int64 {
 	return out
 }
 
-// copyStatusCounts renders the int-keyed status counter as the string-keyed wire
-// map the AdminMetrics JSON shape declares. The caller must hold m.mu while copying.
+// copyStatusCounts 把 int 键的状态计数器渲染为 AdminMetrics JSON
+// 形状所声明的字符串键线上 map。调用方在复制时必须持有 m.mu。
 func copyStatusCounts(src map[int]int64) map[string]int64 {
 	out := make(map[string]int64, len(src))
 	for k, v := range src {