[fix](trx-frontend-http): route feature bundles through the host contract

The bookmark fix addressed one instance of a defect the TypeScript
migration left across the feature entries.  app.js stopped being a
classic script, so its top-level declarations are no longer shared
globals, but the converted entries kept reading them as window
properties that nothing publishes.

Restore the broken behavior:

- ais, aprs, hf-aprs read serverLat, serverLon and haversineKm as
  undefined, so every positioned packet rendered an empty distance.
- ais, aprs, hf-aprs, cw, sat, vdes, wefax, wspr called an undefined
  postPath, so clear-history and decoder toggles threw.
- scheduler read authRole as undefined, so the lazy-load path never
  self-initialized and the Settings tab opened an inert scheduler.
- background-decode read authEnabled as undefined, so control gating
  fell back to role-only.
- vchan read fifteen application values and services as undefined:
  mode and bandwidth sync, the out-of-band hint, RX audio restart, and
  the frequency field all silently no-opped on a virtual channel.
- vchan wrapped window.refreshFreqDisplay, capturing an undefined
  original exactly as it did for setRigFrequency, so leaving a channel
  never restored the application's own frequency display.
- _audioChannelOverride was a const that nothing could assign, so RX
  audio always subscribed to the primary channel.
- ftx-family read fmtTime, a helper legacy ft8.js owned locally, so
  decode bar timestamps rendered empty.

Declare the contract once in plugins/host.ts and import it from the
feature entries, rather than restoring globals that
docs/frontend-architecture.md excludes.  trx.state gains jogUnit,
rxActive and audioChannelOverride, and makes lastModeName writable;
trx.core gains the tuning, RDS, WFM, jog and RX audio services the
entries need.  vchan interception moves to an interceptFreqDisplay
service method that refreshFreqDisplay calls, matching the frequency,
mode and bandwidth interception it already registers.

Reading registry-built elements through a strict lookup is the same
defect as in bookmarks: renderTimelineNeedle guards its result, but
schedulerEl throws, so the now-initializing scheduler crashed on the
timeline needle group that its own SVG creates.

Feature tests move onto a shared host fixture, and entries that now
import a common module are bundled through bundleEntry like the other
shared-module entries.  Covers scheduler self-initialization and the
distance path that the bare window reads broke.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GdyUjuXejCEfiub675z6cz
Signed-off-by: Stan Grams <sjg@haxx.space>

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

@@ -8,12 +8,16 @@ import {
   renderAprsInfo,
   renderLocalAprsSymbol
 } from "./chunk-M2I6DH4X.js";
+import {
+  hostCore,
+  hostState
+} from "./chunk-KL66PICH.js";
 
 // src/plugins/aprs.ts
 var aprsWindow = window;
-var escapeAprsHtml = (input) => aprsWindow.escapeMapHtml?.(input) ?? input.replaceAll("&", "&amp;").replaceAll("<", "&lt;").replaceAll(">", "&gt;").replaceAll('"', "&quot;");
+var escapeAprsHtml = (input) => hostCore.escapeMapHtml(input);
 var showAprsHint = (message, durationMs) => {
-  aprsWindow.showHint?.(message, durationMs);
+  hostCore.showHint(message, durationMs);
 };
 var aprsStatus = document.getElementById("aprs-status");
 var aprsPacketsEl = document.getElementById("aprs-packets");
@@ -58,8 +62,8 @@ function scheduleAprsBarUpdate() {
   });
 }
 function aprsDistanceText(pkt) {
-  if (aprsWindow.serverLat == null || aprsWindow.serverLon == null || pkt.lat == null || pkt.lon == null || !aprsWindow.haversineKm) return "";
-  const distKm = aprsWindow.haversineKm(aprsWindow.serverLat, aprsWindow.serverLon, pkt.lat, pkt.lon);
+  if (hostState.serverLat == null || hostState.serverLon == null || pkt.lat == null || pkt.lon == null) return "";
+  const distKm = hostCore.haversineKm(hostState.serverLat, hostState.serverLon, pkt.lat, pkt.lon);
   if (!Number.isFinite(distKm)) return "";
   if (distKm < 1) return `${Math.round(distKm * 1e3)} m from TRX`;
   return `${distKm.toFixed(1)} km from TRX`;
@@ -260,7 +264,7 @@ document.getElementById("settings-clear-aprs-history")?.addEventListener("click"
   void (async () => {
     if (!await aprsWindow.trxUi.confirm({ title: "Clear APRS history?", message: "All stored APRS packets will be permanently removed.", confirmLabel: "Clear history" })) return;
     try {
-      await aprsWindow.postPath?.("/clear_aprs_decode");
+      await hostCore.postPath("/clear_aprs_decode");
       resetAprsHistoryView();
     } catch (e) {
       console.error("APRS history clear failed", e);