feat: weather precip/wind, dashboard mic, remove global voice overlay

- WeatherCard: show precipitation (mm) and max wind speed per forecast day
- DashboardChatInput: add PTT mic button (transcribe-to-input, voice-gated)
- Remove global VoiceOverlay floating button and Space PTT shortcut from
  App.vue — inline mic buttons in chat/briefing/dashboard are the right UX;
  global overlay had focus/latency/context issues

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/components/WeatherCard.vue

@@ -6,6 +6,8 @@ interface ForecastDay {
   condition: string
   high: number
   low: number
+  precip_mm: number
+  windspeed_max: number
 }
 
 interface WeatherData {
@@ -86,6 +88,9 @@ const fetchedAtLabel = computed(() => {
         <span class="forecast-day-name">{{ day.day }}</span>
         <span class="forecast-icon">{{ weatherIcon(day.condition) }}</span>
         <span class="forecast-temps">{{ day.high }}° / {{ day.low }}°</span>
+        <span v-if="day.precip_mm > 0" class="forecast-precip">💧 {{ day.precip_mm }}mm</span>
+        <span v-else class="forecast-precip forecast-precip--dry">—</span>
+        <span class="forecast-wind">💨 {{ day.windspeed_max }}km/h</span>
       </div>
     </div>
   </div>
@@ -185,6 +190,17 @@ const fetchedAtLabel = computed(() => {
   white-space: nowrap;
 }
 
+.forecast-precip,
+.forecast-wind {
+  font-size: 0.72rem;
+  white-space: nowrap;
+  color: var(--color-text-muted);
+}
+
+.forecast-precip--dry {
+  opacity: 0.35;
+}
+
 .weather-unavailable {
   color: var(--color-text-muted);
   font-style: italic;