feat(access-logs): 上报并展示边缘缓存状态 cache_status

OpenResty 日志输出 $upstream_cache_status；Agent/协议/ClickHouse 贯通入库。
明细列表与详情按 HIT/MISS 等推导命中、回源、未缓存三态标签。

internal/apps/agent/observability/traffic.go

@@ -23,6 +23,7 @@ type accessLogRecord struct {
 	RemoteAddr    string  `json:"remote_addr"`
 	Path          string  `json:"path"`
 	UserAgent     string  `json:"user_agent"`
+	CacheStatus   string  `json:"cache_status"`
 	Status        int     `json:"status"`
 	BytesSent     int64   `json:"bytes_sent"`
 	RequestLength int64   `json:"request_length"`
@@ -147,6 +148,7 @@ func (aggregate *trafficAggregate) consume(line []byte) {
 		Host:          strings.TrimSpace(record.Host),
 		Path:          normalizeAccessLogPath(record.Path),
 		UserAgent:     strings.TrimSpace(record.UserAgent),
+		CacheStatus:   normalizeCacheStatus(record.CacheStatus),
 		StatusCode:    record.Status,
 		BytesSent:     record.BytesSent,
 		RequestLength: record.RequestLength,
@@ -160,6 +162,7 @@ type parsedAccessLogRecord struct {
 	RemoteAddr    string
 	Path          string
 	UserAgent     string
+	CacheStatus   string
 	Status        int
 	BytesSent     int64
 	RequestLength int64
@@ -193,6 +196,7 @@ func parseJSONAccessLogRecord(raw string) (parsedAccessLogRecord, bool) {
 		RemoteAddr:    strings.TrimSpace(record.RemoteAddr),
 		Path:          normalizeAccessLogPath(record.Path),
 		UserAgent:     strings.TrimSpace(record.UserAgent),
+		CacheStatus:   normalizeCacheStatus(record.CacheStatus),
 		Status:        record.Status,
 		BytesSent:     record.BytesSent,
 		RequestLength: record.RequestLength,
@@ -200,6 +204,14 @@ func parseJSONAccessLogRecord(raw string) (parsedAccessLogRecord, bool) {
 	}, true
 }
 
+func normalizeCacheStatus(value string) string {
+	trimmed := strings.TrimSpace(value)
+	if trimmed == "-" {
+		return ""
+	}
+	return trimmed
+}
+
 func parseCombinedAccessLogRecord(raw string) (parsedAccessLogRecord, bool) {
 	matches := combinedAccessLogPattern.FindStringSubmatch(raw)
 	if len(matches) != combinedAccessLogMatchGroupCount {

internal/apps/agent/observability/traffic_test.go

@@ -14,8 +14,8 @@ func TestCollectAccessLogsReturnsFactsOnly(t *testing.T) {
 	tempDir := t.TempDir()
 	logPath := filepath.Join(tempDir, "openflare_access.log")
 	content := []byte(
-		"{\"ts\":\"2026-03-14T08:00:00Z\",\"host\":\"app.example.com\",\"path\":\"/login\",\"remote_addr\":\"10.0.0.1\",\"status\":200,\"request_length\":128,\"bytes_sent\":512,\"request_time\":0.015,\"user_agent\":\"Mozilla/5.0\"}\n" +
-			"{\"ts\":\"2026-03-14T08:00:05Z\",\"host\":\"api.example.com\",\"path\":\"/v1/ping\",\"remote_addr\":\"10.0.0.2\",\"status\":502,\"request_length\":64,\"bytes_sent\":256,\"request_time\":0.008,\"user_agent\":\"curl/8.0\"}\n",
+		"{\"ts\":\"2026-03-14T08:00:00Z\",\"host\":\"app.example.com\",\"path\":\"/login\",\"remote_addr\":\"10.0.0.1\",\"status\":200,\"request_length\":128,\"bytes_sent\":512,\"request_time\":0.015,\"user_agent\":\"Mozilla/5.0\",\"cache_status\":\"HIT\"}\n" +
+			"{\"ts\":\"2026-03-14T08:00:05Z\",\"host\":\"api.example.com\",\"path\":\"/v1/ping\",\"remote_addr\":\"10.0.0.2\",\"status\":502,\"request_length\":64,\"bytes_sent\":256,\"request_time\":0.008,\"user_agent\":\"curl/8.0\",\"cache_status\":\"MISS\"}\n",
 	)
 	if err := os.WriteFile(logPath, content, 0o644); err != nil {
 		t.Fatalf("WriteFile failed: %v", err)
@@ -38,6 +38,9 @@ func TestCollectAccessLogsReturnsFactsOnly(t *testing.T) {
 	if accessLogs[0].UserAgent != "Mozilla/5.0" || accessLogs[1].UserAgent != "curl/8.0" {
 		t.Fatalf("unexpected user agents: %+v", accessLogs)
 	}
+	if accessLogs[0].CacheStatus != "HIT" || accessLogs[1].CacheStatus != "MISS" {
+		t.Fatalf("unexpected cache status: %+v", accessLogs)
+	}
 
 	snapshot, err := stateStore.Load()
 	if err != nil {

internal/apps/openflare/agent/observability.go

@@ -24,7 +24,8 @@ const (
 	healthSeverityWarning       = "warning"
 	healthSeverityCritical      = "critical"
 	accessLogPathMaxLength      = 100
-	accessLogUserAgentMaxLength = 512
+	accessLogUserAgentMaxLength   = 512
+	accessLogCacheStatusMaxLength = 32
 	healthEventMessageMaxLength = 4096
 )
 
@@ -210,6 +211,7 @@ func buildNodeAccessLogRecords(nodeID string, direct []NodeAccessLog, buffered [
 				Host:          strings.TrimSpace(item.Host),
 				Path:          truncateForDatabase(strings.TrimSpace(item.Path), accessLogPathMaxLength),
 				UserAgent:     truncateForDatabase(strings.TrimSpace(item.UserAgent), accessLogUserAgentMaxLength),
+				CacheStatus:   truncateForDatabase(strings.TrimSpace(item.CacheStatus), accessLogCacheStatusMaxLength),
 				StatusCode:    item.StatusCode,
 				BytesSent:     bytesSent,
 				RequestLength: requestLength,

internal/apps/openflare/observability/access_log_logics.go

@@ -46,16 +46,17 @@ type AccessLogQuery struct {
 
 // AccessLogView is a single access log row.
 type AccessLogView struct {
-	ID         string    `json:"id"`
-	NodeID     string    `json:"node_id"`
-	NodeName   string    `json:"node_name"`
-	LoggedAt   time.Time `json:"logged_at"`
-	RemoteAddr string    `json:"remote_addr"`
-	Region     string    `json:"region"`
-	Host       string    `json:"host"`
-	Path       string    `json:"path"`
-	UserAgent  string    `json:"user_agent"`
-	StatusCode int       `json:"status_code"`
+	ID          string    `json:"id"`
+	NodeID      string    `json:"node_id"`
+	NodeName    string    `json:"node_name"`
+	LoggedAt    time.Time `json:"logged_at"`
+	RemoteAddr  string    `json:"remote_addr"`
+	Region      string    `json:"region"`
+	Host        string    `json:"host"`
+	Path        string    `json:"path"`
+	UserAgent   string    `json:"user_agent"`
+	CacheStatus string    `json:"cache_status"`
+	StatusCode  int       `json:"status_code"`
 }
 
 // AccessLogList is a paginated access log response.
@@ -476,16 +477,17 @@ func ListAccessLogs(ctx context.Context, input AccessLogQuery) (*AccessLogList,
 			continue
 		}
 		views = append(views, AccessLogView{
-			ID:         formatAccessLogID(item.ID),
-			NodeID:     item.NodeID,
-			NodeName:   nodeNames[item.NodeID],
-			LoggedAt:   item.LoggedAt,
-			RemoteAddr: item.RemoteAddr,
-			Region:     item.Region,
-			Host:       item.Host,
-			Path:       item.Path,
-			UserAgent:  item.UserAgent,
-			StatusCode: item.StatusCode,
+			ID:          formatAccessLogID(item.ID),
+			NodeID:      item.NodeID,
+			NodeName:    nodeNames[item.NodeID],
+			LoggedAt:    item.LoggedAt,
+			RemoteAddr:  item.RemoteAddr,
+			Region:      item.Region,
+			Host:        item.Host,
+			Path:        item.Path,
+			UserAgent:   item.UserAgent,
+			CacheStatus: item.CacheStatus,
+			StatusCode:  item.StatusCode,
 		})
 	}
 	return &AccessLogList{