[feat](trx-frontend-http): add Clear button to APRS decode panel

Clears the packet list, map markers are unaffected.  Also wipes
the persisted packet history from localStorage.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Stanislaw Grams <stanislawgrams@gmail.com>

src/trx-client/trx-frontend/trx-frontend-http/assets/web/index.html

@@ -146,6 +146,7 @@
       <div id="subtab-aprs" class="sub-tab-panel" style="display:none;">
         <div class="aprs-controls">
           <button id="aprs-toggle-btn" type="button">Start APRS</button>
+          <button id="aprs-clear-btn" type="button">Clear</button>
           <small id="aprs-status" style="color:var(--text-muted);">Stopped</small>
         </div>
         <div id="aprs-packets"></div>

src/trx-client/trx-frontend/trx-frontend-http/assets/web/plugins/aprs.js

@@ -634,6 +634,12 @@ aprsToggleBtn.addEventListener("click", () => {
   if (aprsActive) { stopAprs(true); } else { startAprs(); }
 });
 
+document.getElementById("aprs-clear-btn").addEventListener("click", () => {
+  aprsPacketsEl.innerHTML = "";
+  aprsPacketHistory = [];
+  saveSetting("aprsPackets", []);
+});
+
 // Restore saved packets and map markers on page load
 for (let i = aprsPacketHistory.length - 1; i >= 0; i--) {
   const pkt = aprsPacketHistory[i];