Upgrade live timing page for race weekends

- Track status flag banner (green/yellow/SC/VSC/red, defensive mapping)
- Weather strip: air/track temp, humidity, wind with compass, rain badge
- Gap trend sparklines from a per-driver interval ring buffer
- Battle detection: consecutive cars within 1.0s chained and highlighted
- Stint history column with compound sequence per driver
- Pinnable drivers (max 3) with focus cards, persisted to localStorage

Pure logic lives in lib/gapHistory.ts and lib/battles.ts with unit
tests; 137 frontend tests passing.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/src/components/live/WeatherStrip.tsx

@@ -0,0 +1,51 @@
+import type { LiveWeatherData } from '../../types'
+import { windDirectionLabel } from '../../lib/live'
+
+interface Props {
+  weather: LiveWeatherData | null | undefined
+}
+
+export function WeatherStrip({ weather }: Props) {
+  if (!weather) return null
+  const hasData =
+    weather.AirTemp > 0 ||
+    weather.TrackTemp > 0 ||
+    weather.Humidity > 0 ||
+    weather.WindSpeed > 0 ||
+    weather.Rainfall
+  if (!hasData) return null
+
+  const windDir = windDirectionLabel(weather.WindDir)
+
+  return (
+    <div className="live-weather-strip" data-testid="weather-strip">
+      {weather.AirTemp > 0 && (
+        <span className="weather-item">
+          <span className="weather-k">air</span>
+          <span className="weather-v">{weather.AirTemp.toFixed(0)}°C</span>
+        </span>
+      )}
+      {weather.TrackTemp > 0 && (
+        <span className="weather-item">
+          <span className="weather-k">track</span>
+          <span className="weather-v">{weather.TrackTemp.toFixed(0)}°C</span>
+        </span>
+      )}
+      {weather.Humidity > 0 && (
+        <span className="weather-item">
+          <span className="weather-k">hum</span>
+          <span className="weather-v">{weather.Humidity.toFixed(0)}%</span>
+        </span>
+      )}
+      {weather.WindSpeed > 0 && (
+        <span className="weather-item">
+          <span className="weather-k">wind</span>
+          <span className="weather-v">
+            {weather.WindSpeed.toFixed(1)} m/s{windDir ? ` ${windDir}` : ''}
+          </span>
+        </span>
+      )}
+      {weather.Rainfall && <span className="badge badge-wet">RAIN</span>}
+    </div>
+  )
+}