[feat](trx-frontend-http): wire HF APRS toggle button and bookmark decoder

- Add "Enable HF APRS" toggle button to the HF APRS tab (same style as
  FT8/WSPR); button is disabled during TX like other decoder toggles
- app.js: sync button text/colour from SSE state updates
- hf-aprs.js: connect button click to /toggle_hf_aprs_decode
- bookmarks.js: add "HF APRS" checkbox to Add/Edit Bookmark decoder
  section; bmReadDecoders/bmWriteDecoders handle "hf-aprs" key; bmApply
  toggles the decoder to match bookmark preference on recall

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>

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

@@ -327,6 +327,10 @@ function addHfAprsPacket(pkt) {
   renderHfAprsHistory();
 }
 
+document.getElementById("hf-aprs-decode-toggle-btn")?.addEventListener("click", async () => {
+  try { await postPath("/toggle_hf_aprs_decode"); } catch (e) { console.error("HF APRS toggle failed", e); }
+});
+
 document.getElementById("hf-aprs-clear-btn")?.addEventListener("click", async () => {
   try {
     await postPath("/clear_hf_aprs_decode");