analysis: split TCP retransmissions into forward and return, and show both on the line cards

tcp.retrans.up counts retransmitted segments sent by the dialing side, tcp.retrans.down those sent by the listening side. The cards show RTT as a round trip (⇄) with forward (→) and return (←) rows for QUIC loss and TCP retransmission.

web/display/src/pages/Line.tsx

@@ -38,7 +38,8 @@ const TILES: { group: Exclude<MetricGroup, 'score'>; label: string; key: string;
   { group: 'tcp-connect', label: 'TCP RTT p50', key: 'tcp.rtt.p50', fmt: fmtMs },
   { group: 'tcp-connect', label: 'TCP RTT p99', key: 'tcp.rtt.p99', fmt: fmtMs },
   { group: 'tcp-connect', label: 'TCP RTT 最大', key: 'tcp.rtt.max', fmt: fmtMs },
-  { group: 'tcp-connect', label: 'TCP 重传率', key: 'tcp.retrans', fmt: fmtPct, good: 0.5, poor: 3 },
+  { group: 'tcp-connect', label: 'TCP 去程重传率', key: 'tcp.retrans.up', fmt: fmtPct, good: 0.5, poor: 3 },
+  { group: 'tcp-connect', label: 'TCP 回程重传率', key: 'tcp.retrans.down', fmt: fmtPct, good: 0.5, poor: 3 },
   { group: 'tcp-connect', label: 'TCP 建连 p95', key: 'connect.tcp_ms.p95', fmt: fmtMs, optional: true },
   { group: 'tcp-connect', label: 'TLS 握手 p95', key: 'connect.tls_ms.p95', fmt: fmtMs, optional: true },
   { group: 'tcp-connect', label: '建连成功率', key: 'connect.success', fmt: fmtPct, optional: true },
@@ -64,11 +65,11 @@ const GROUPS = [
 
 const CHARTS: ChartDef[] = [
   { id: 'rtt', title: '延迟', group: 'quic', unit: 'ms', series: [{ key: 'rtt.p50', label: 'p50', color: '--chart-1' }, { key: 'rtt.p95', label: 'p95', color: '--chart-2' }, { key: 'rtt.p99', label: 'p99', color: '--chart-3' }] },
-  { id: 'jitter', title: '抖动（p95）', group: 'quic', unit: 'ms', series: [{ key: 'jitter.up.p95', label: '上行', color: '--chart-2' }, { key: 'jitter.down.p95', label: '下行', color: '--chart-1' }] },
-  { id: 'loss', title: '丢包', group: 'quic', unit: '%', series: [{ key: 'loss.up', label: '上行', color: '--chart-2' }, { key: 'loss.down', label: '下行', color: '--chart-3' }, { key: 'loss.total', label: '合计', color: '--chart-1', dash: [4, 3] }] },
-  { id: 'loss-runs', title: '最长连续丢包', group: 'quic', unit: '包', series: [{ key: 'loss.run.up_max', label: '上行', color: '--chart-2' }, { key: 'loss.run.down_max', label: '下行', color: '--chart-3' }] },
+  { id: 'jitter', title: '抖动（p95）', group: 'quic', unit: 'ms', series: [{ key: 'jitter.up.p95', label: '去程', color: '--chart-2' }, { key: 'jitter.down.p95', label: '回程', color: '--chart-1' }] },
+  { id: 'loss', title: '丢包', group: 'quic', unit: '%', series: [{ key: 'loss.up', label: '去程', color: '--chart-2' }, { key: 'loss.down', label: '回程', color: '--chart-3' }, { key: 'loss.total', label: '合计', color: '--chart-1', dash: [4, 3] }] },
+  { id: 'loss-runs', title: '最长连续丢包', group: 'quic', unit: '包', series: [{ key: 'loss.run.up_max', label: '去程', color: '--chart-2' }, { key: 'loss.run.down_max', label: '回程', color: '--chart-3' }] },
   { id: 'tcp', title: '往返时延（RTT）', group: 'tcp-connect', unit: 'ms', series: [{ key: 'tcp.rtt.p50', label: 'p50', color: '--chart-1' }, { key: 'tcp.rtt.p95', label: 'p95', color: '--chart-2' }, { key: 'tcp.rtt.max', label: '最大', color: '--chart-3' }] },
-  { id: 'retrans', title: '重传率', group: 'tcp-connect', unit: '%', fill: true, series: [{ key: 'tcp.retrans', label: '重传率', color: '--chart-3' }] },
+  { id: 'retrans', title: '重传率', group: 'tcp-connect', unit: '%', series: [{ key: 'tcp.retrans.up', label: '去程', color: '--chart-2' }, { key: 'tcp.retrans.down', label: '回程', color: '--chart-3' }, { key: 'tcp.retrans', label: '合计', color: '--chart-1', dash: [4, 3] }] },
   { id: 'connect-time', title: '建连耗时（p95）', group: 'tcp-connect', unit: 'ms', series: [{ key: 'connect.tcp_ms.p95', label: 'TCP 建连', color: '--chart-1' }, { key: 'connect.tls_ms.p95', label: 'TLS 握手', color: '--chart-2' }] },
   { id: 'connect-ok', title: '建连成功率', group: 'tcp-connect', unit: '%', zero: false, series: [{ key: 'connect.success', label: '成功率', color: '--chart-3' }] },
   { id: 'score', title: '综合评分', group: 'score', wide: true, unit: '', series: [{ key: 'score.reality', label: 'REALITY', color: '--chart-1' }, { key: 'score.hy2', label: 'Hy2', color: '--chart-2' }, { key: 'score.mc', label: 'MC', color: '--chart-4' }, { key: 'score.base', label: '综合', color: '--chart-5', dash: [4, 3] }] },
@@ -316,7 +317,7 @@ export function Line() {
               <div className="line-combo-card">
                 <h3>QUIC Datagram 丢包</h3>
                 <div className="line-combo-primary"><span>总丢包</span><strong className={`combo-tone-${tone(m['loss.total'], 0.5, 3)}`}>{fmtPct(m['loss.total'])}</strong></div>
-                <div className="line-combo-secondary"><span>↑ {fmtPct(m['loss.up'])}</span><span>/</span><span>↓ {fmtPct(m['loss.down'])}</span></div>
+                <div className="line-combo-secondary"><span>去 {fmtPct(m['loss.up'])}</span><span>/</span><span>回 {fmtPct(m['loss.down'])}</span></div>
                 <span className="line-combo-badge">最长连续 ↑ {fmtNum(m['loss.run.up_max'])} / ↓ {fmtNum(m['loss.run.down_max'])} 包</span>
               </div>
               <div className="line-combo-card">