feat(pm): live ATIS broadcast loop with METAR-slot refresh and multi-station support

- per-airport ATIS loop keyed by station with a virtual start epoch, so
  re-tuning resumes where the broadcast would be instead of restarting
- refetch airport data at :23/:53 to follow VATSIM ATIS regeneration from
  real-world METAR publication, with faster retries while no ATIS is on
  the feed; prefetch audio when the info letter changes
- support separate arrival/departure ATIS stations on different frequencies
- cancel the deferred audio teardown on retune so a fresh broadcast is not
  killed by the previous stop()'s fade-out timer (atisAudioLoop)
- comm log shows newest entries first

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

app/components/CommLog.vue

@@ -42,8 +42,9 @@ const formatTime = (date: Date): string => {
       </div>
 
       <div class="space-y-2 overflow-y-auto" :class="dense ? 'max-h-[70vh]' : 'max-h-64'">
+        <!-- Newest first: the latest exchange is always visible without scrolling. -->
         <div
-            v-for="entry in entries.slice(-limit)"
+            v-for="entry in entries.slice(-limit).reverse()"
             :key="entry.timestamp.getTime?.() ?? entry.timestamp"
             class="rounded-2xl border border-white/10 bg-black/40 p-3"
         >