[fix](trx-frontend-http): replay what arrived before a lazy view loaded

Opening the Map or Statistics page showed only what had been decoded since
the moment it was opened, and a reload — landing straight on the tab, so its
module loads at startup ahead of the history — was the only way to see the
rest.  Two things were being thrown away.

The decode log the Statistics page counts lives in the map module, which is
lazy.  Recording into a module that is not loaded yet is a no-op, and unlike
the map markers nothing replayed the log when it finally arrived, so every
decode heard before the first visit was simply never counted.  Hold those
records in the client and hand them over when the module attaches.

The map's own replay covered APRS, AIS and VDES, whose plugins implement
syncMap, but not the grid squares: the FTx family and WSPR plotted locators
as decodes arrived and had no replay at all, so everything they heard before
the map loaded was lost, and the unique-grid counter with it.  Both plot
through a helper now, which their syncMap replays oldest first.  A replayed
WSPR spot carries the frequency it was heard on rather than one worked out
against wherever the dial has moved to since.

Pinned in decode-flow, whose history fixture gains FT8 and WSPR spots: after
a first visit the statistics count every stored decode and every grid square,
which before this change were 0 and 0.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SyX26FCpMQxiBoC7r5K1A7
Signed-off-by: Stan Grams <sjg@haxx.space>

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/plugins/wspr.ts

@@ -17,6 +17,9 @@ interface WsprMessage {
   dt_s?: number | undefined;
   freq_hz?: number | undefined;
   rig_id?: string | null | undefined;
+  /** RF frequency the spot was heard on, kept so a map replay does not
+   *  recompute it against wherever the dial has moved to since. */
+  _rfHz?: number | null | undefined;
   receiver?: unknown;
   [key: string]: unknown;
 }
@@ -135,6 +138,7 @@ function normalizeServerWsprMessage(msg: WsprMessage): { raw: string; grids: str
     rfHz,
     history: {
       rig_id: msg.rig_id ?? null,
+      _rfHz: rfHz,
       receiver: wsprWindow.getDecodeRigMeta ? wsprWindow.getDecodeRigMeta() : null,
       ts_ms: msg.ts_ms,
       snr_db: msg.snr_db,
@@ -152,12 +156,7 @@ function onServerWsprBatch(messages: WsprMessage[]): void {
     const next = normalizeServerWsprMessage(msg);
     // "Receiving" is the panel's own status, and the panel is the rig's.
     if (wsprStatus && isActiveRigDecode(msg.rig_id)) wsprStatus.textContent = "Receiving";
-    if (next.grids.length > 0 && wsprWindow.mapAddLocator) {
-      wsprWindow.mapAddLocator(next.raw, next.grids, "wspr", next.station, {
-        ...msg,
-        ...(next.rfHz === null ? {} : { freq_hz: next.rfHz }),
-      });
-    }
+    plotWsprLocator(msg);
     next.history._tsMs = Number.isFinite(next.history.ts_ms) ? Number(next.history.ts_ms) : Date.now();
     normalized.push(next.history);
   }
@@ -317,15 +316,24 @@ document.getElementById("settings-clear-wspr-history")?.addEventListener("click"
   })();
 });
 
+/** Hands a spot's grid squares to the map, if the map module is loaded yet.
+ *  The module is lazy, so a spot heard before it arrived has to be replayable. */
+function plotWsprLocator(msg: WsprMessage): void {
+  const next = normalizeServerWsprMessage(msg);
+  if (next.grids.length === 0 || !wsprWindow.mapAddLocator) return;
+  // A replayed spot carries the frequency it was heard on; a fresh one has it
+  // worked out from the dial it just arrived against.
+  const rfHz = finiteNumber(msg._rfHz) ?? next.rfHz;
+  wsprWindow.mapAddLocator(next.raw, next.grids, "wspr", next.station, {
+    ...msg,
+    ...(rfHz === null ? {} : { freq_hz: rfHz }),
+  });
+}
+
 function onServerWspr(msg: WsprMessage): void {
   if (wsprStatus && isActiveRigDecode(msg.rig_id)) wsprStatus.textContent = "Receiving";
   const next = normalizeServerWsprMessage(msg);
-  if (next.grids.length > 0 && wsprWindow.mapAddLocator) {
-    wsprWindow.mapAddLocator(next.raw, next.grids, "wspr", next.station, {
-      ...msg,
-      ...(next.rfHz === null ? {} : { freq_hz: next.rfHz }),
-    });
-  }
+  plotWsprLocator(msg);
   addWsprMessage(next.history);
 }
 
@@ -337,4 +345,6 @@ wsprWindow.trxPluginRuntime.registerDecoder({
   prune: pruneWsprHistoryView,
   reset: resetWsprHistoryView,
   rerender: renderWsprHistory,
+  // Oldest first, so the map builds the grids up in the order they were heard.
+  syncMap: () => { for (const message of [...wsprMessageHistory].reverse()) plotWsprLocator(message); },
 });