UX 审查修复：统一修正术语、图表"现在"标记、专业术语解释、异常行动建议

P0-1 术语统一：
- WeatherDecisionBand 改用"上修/下修/维持"替代"偏高温/暂不追/等待确认"
- 与 AI 后端提示词使用的术语体系一致

P0-9 图表"现在"标记：
- chart-utils.ts 导出 currentIndex
- AiCityTemperatureChart 在 currentIndex 处绘制竖线（蓝色虚线）

P0-13 专业术语解释：
- DataFreshnessBar 新增 labelTitle 属性（hover tooltip）
- METAR → "机场气象观测报文" / "Meteorological Aerodrome Report"
- HKO → "香港天文台官方实测" / "Hong Kong Observatory official readings"

P0-16 异常行动建议：
- primaryReason 追加行动指引（实测突破→建议关注偏高温区间等待确认 / 峰值已过→建议避免追高 / 观测过旧→建议等待新报文）

P1-8 DEB 路径分段样式：
- 过去部分实线（已确定），未来部分虚线（预测不确定）

P1-11 HistoryChart 单位：
- tooltip 使用 temp_symbol 替代硬编码 °

Tested: npx tsc --noEmit

frontend/components/dashboard/HistoryChart.tsx

@@ -125,7 +125,7 @@ export function HistoryChart() {
             titleFont: { family: "Inter", size: 13, weight: 600 },
             callbacks: {
               label: (ctx) =>
-                `${ctx.dataset.label}: ${ctx.parsed.y?.toFixed(1)}°`,
+                `${ctx.dataset.label}: ${ctx.parsed.y?.toFixed(1)}${store.selectedDetail?.temp_symbol || "°C"}`,
             },
           },
         },

frontend/components/dashboard/scan-terminal/AiCityTemperatureChart.tsx

@@ -109,7 +109,6 @@ export function AiCityTemperatureChart({ detail }: { detail: CityDetail }) {
     >["datasets"] = [
       {
         borderColor: "rgba(100, 116, 139, 0.72)",
-        borderDash: [6, 4],
         borderWidth: 1.6,
         data: chartData.datasets.debPast.map(
           (value, index) => value ?? chartData.datasets.debFuture[index],
@@ -117,6 +116,10 @@ export function AiCityTemperatureChart({ detail }: { detail: CityDetail }) {
         fill: false,
         label: forecastLabel,
         pointRadius: 0,
+        segment: {
+          borderDash: (ctx: { p0DataIndex: number }) =>
+            chartData.currentIndex != null && ctx.p0DataIndex < chartData.currentIndex ? [] : [6, 4],
+        },
         spanGaps: true,
         tension: 0.28,
       },
@@ -148,6 +151,23 @@ export function AiCityTemperatureChart({ detail }: { detail: CityDetail }) {
       showLine: false,
     });
 
+    const ci = chartData.currentIndex;
+    if (ci != null && ci >= 0 && ci < (chartData.times?.length || 0)) {
+      datasets.push({
+        backgroundColor: "rgba(77, 163, 255, 0.5)",
+        borderColor: "rgba(77, 163, 255, 0.5)",
+        borderDash: [3, 4],
+        borderWidth: 1.2,
+        data: [
+          { x: ci, y: chartData.max },
+          { x: ci, y: chartData.min },
+        ],
+        label: "Now",
+        pointRadius: 0,
+        showLine: true,
+      });
+    }
+
     return {
       data: {
         datasets,
@@ -165,7 +185,7 @@ export function AiCityTemperatureChart({ detail }: { detail: CityDetail }) {
             borderColor: "rgba(77, 163, 255, 0.38)",
             borderWidth: 1,
           },
-        },
+        } as Record<string, unknown>,
         responsive: true,
         scales: {
           x: {

frontend/components/dashboard/scan-terminal/AiPinnedCityCard.tsx

@@ -461,6 +461,9 @@ export function AiPinnedCityCard({
   const dataFreshnessRows = [
     {
       label: isHkoObservation ? (isEn ? "HKO" : "天文台") : "METAR",
+      labelTitle: isHkoObservation
+        ? (isEn ? "Hong Kong Observatory official readings" : "香港天文台官方实测")
+        : (isEn ? "Meteorological Aerodrome Report — airport weather observation" : "机场气象观测报文"),
       value: buildObservationFreshnessValue({
         detail,
         displayTime: metarReportTimeDisplay,

frontend/components/dashboard/scan-terminal/DataFreshnessBar.tsx

@@ -4,6 +4,7 @@ import type { StatusTone } from "@/components/dashboard/scan-terminal/CityStatus
 
 export type DataFreshnessRow = {
   label: string;
+  labelTitle?: string;
   value: string;
   tone: string;
 };
@@ -26,7 +27,7 @@ export function DataFreshnessBar({
       <strong>{isEn ? "Data freshness" : "数据新鲜度"}</strong>
       {rows.map((freshness) => (
         <span key={freshness.label} className={freshness.tone}>
-          <b>{freshness.label}{freshnessSeparator}</b>
+          <b title={freshness.labelTitle}>{freshness.label}{freshnessSeparator}</b>
           <em>{freshness.value}</em>
         </span>
       ))}

frontend/components/dashboard/scan-terminal/city-card-decision-utils.ts

@@ -555,15 +555,15 @@ export function buildWeatherDecisionView({
         : "等待模型补齐"
       : paceTone === "warm"
         ? isEn
-          ? "Watch hotter range"
-          : "关注偏高温区间"
+          ? "Revise upward"
+          : "预计最高温上修"
         : paceTone === "cold"
           ? isEn
-            ? "Avoid chasing high"
-            : "暂不追高温"
+            ? "Revise downward"
+            : "预计最高温下修"
           : isEn
-            ? "Wait for peak-window confirmation"
-            : "等待峰值窗口确认";
+            ? "Stay with model base"
+            : "维持模型基准";
   const expectedHigh =
     center != null && Number.isFinite(Number(center))
       ? formatTemperatureValue(Number(center), tempSymbol, { digits: 1 })

frontend/components/dashboard/scan-terminal/city-decision-state.ts

@@ -142,28 +142,28 @@ export function buildCityDecisionState({
         : "watch";
   const primaryReason = observedHighBreak
     ? isEn
-      ? "Observation has broken above the model range."
-      : "实测已突破模型上沿。"
+      ? "Observation has broken above the model range. Consider the upside scenario; wait for the next bulletin to confirm the breakout."
+      : "实测已突破模型上沿。建议关注偏高温区间，等待下一报文确认突破是否持续。"
     : peakHasPassed
       ? isEn
-        ? "Peak window has passed; confirm whether a new high can still form."
-        : "峰值窗口已过，确认是否还会出现新高。"
+        ? "Peak window has passed; confirm whether a new high can still form. Avoid chasing if no new high prints."
+        : "峰值窗口已过，确认是否还会出现新高。若无新高，建议避免追高。"
       : observationStale
         ? isEn
-          ? "Observation is stale and needs the next report."
-          : "观测已过旧，需要下一报文确认。"
+          ? "Observation is stale and needs the next report. Use only as background reference until fresh data arrives."
+          : "观测已过旧，需要下一报文确认。当前数据仅作背景参考，建议等待新报文后再做判断。"
         : marketStatus === "unavailable"
           ? isEn
-            ? "Weather evidence is usable, but no tradable quote is available yet."
-            : "天气证据可参考，但暂无可交易价格。"
+            ? "Weather evidence is usable, but no tradable quote is available yet. Weather judgment still applies."
+            : "天气证据可参考，但暂无可交易价格。天气判断仍可参考，无需急于操作。"
           : modelHighlyConsistent
             ? isEn
-              ? "Models are aligned; wait for observation confirmation."
-              : "模型高度一致，等待实测确认。"
+              ? "Models are aligned; wait for observation confirmation. A clear direction should emerge after the next report."
+              : "模型高度一致，等待实测确认。下一报文后方向会更明确。"
             : needsNextBulletin
               ? isEn
-                ? "The next bulletin is more likely to decide direction."
-                : "下一报文更可能决定方向。"
+                ? "The next bulletin is more likely to decide direction. Hold until the picture clears."
+                : "下一报文更可能决定方向。建议等待信号明确后再做决策。"
               : isEn
                 ? "Compare new observations with the expected high through the peak window."
                 : "在峰值窗口内继续对照实测与预计高点。";

frontend/lib/chart-utils.ts

@@ -877,6 +877,7 @@ export function getTemperatureChartData(
   const xMax = times.length ? chartHmToMinutes(times[times.length - 1]) ?? 24 * 60 : 24 * 60;
 
   return {
+    currentIndex,
     datasets: {
       airportMetarPoints,
       airportMetarSeries,