feat: prefer the last QSO's precise locator over the cty.dat centroid; changelog → 0.21.2

For an entity resolved only via cty.dat (e.g. a French call not on QRZ/HamQTH),
the provider block sets a coarse country-centroid grid. The worked-before backfill
now overrides that with the precise locator from the last QSO with this call, and
takes that QSO's lat/lon (derived from the grid when the record stored none) so
the map and saved record stay consistent. A real provider grid still wins.

Moved the (unreleased) worked-before backfill entry into a new 0.21.2 changelog
block, since 0.21.1 is already out.

changelog.json

@@ -1,9 +1,18 @@
 [
+  {
+    "version": "0.21.2",
+    "date": "2026-07-25",
+    "en": [
+      "When a callsign isn't found on QRZ/HamQTH (or you don't use a lookup service), the name, QTH, locator and address are recovered from the last time you worked that station — and the precise locator from that QSO is used instead of the coarse cty.dat country centroid. A real QRZ/HamQTH hit still wins."
+    ],
+    "fr": [
+      "Quand un indicatif est introuvable sur QRZ/HamQTH (ou si tu n'utilises pas de service de lookup), le nom, le QTH, le locator et l'adresse sont récupérés du dernier QSO avec cette station — et c'est le locator précis de ce QSO qui est utilisé, pas le centroïde du pays de cty.dat. Un vrai résultat QRZ/HamQTH reste prioritaire."
+    ]
+  },
   {
     "version": "0.21.1",
     "date": "2026-07-24",
     "en": [
-      "When a callsign isn't found on QRZ/HamQTH (or you don't use a lookup service), the name, QTH, grid and address are now recovered from the last time you worked that station — provider data still wins when there is a hit.",
       "Ctrl + mouse wheel zoom is now remembered across restarts (Ctrl+0 resets to 100%).",
       "Log grid: award column widths are now saved like the other columns, so a width you set survives a restart.",
       "CW keyer widget: added an F9 macro slot, and empty macros are now hidden (like the voice keyer) — fill them in Settings → CW Keyer.",
@@ -19,7 +28,6 @@
       "Fixed award references (in the entry strip's Awards tab) not clearing when the callsign changes — clicking one spot then another no longer keeps the previous station's references."
     ],
     "fr": [
-      "Quand un indicatif est introuvable sur QRZ/HamQTH (ou si tu n'utilises pas de service de lookup), le nom, le QTH, le locator et l'adresse sont maintenant récupérés du dernier QSO avec cette station — les données du service restent prioritaires en cas de résultat.",
       "Le zoom Ctrl + molette est maintenant conservé après un redémarrage (Ctrl+0 remet à 100 %).",
       "Grille du log : les largeurs des colonnes de diplômes sont désormais sauvegardées comme les autres colonnes, une largeur réglée survit au redémarrage.",
       "Widget keyer CW : ajout d'un emplacement de macro F9, et les macros vides sont maintenant masquées (comme le keyer vocal) — remplis-les dans Réglages → Keyer CW.",

frontend/src/App.tsx

@@ -2871,23 +2871,38 @@ export default function App() {
     const empty = (v: any) => (v ?? '') === '';
     if (!ue.has('name') && empty(r?.name) && last.name) setName(last.name);
     if (!ue.has('qth') && empty(r?.qth) && last.qth) setQth(last.qth);
-    if (!ue.has('grid') && empty(r?.grid) && !(r?.lat || r?.lon) && last.grid) setGrid(last.grid);
     if (!ue.has('country') && empty(r?.country) && last.country) setCountry(last.country);
-    setDetails((d) => ({
+    // Grid: a REAL provider grid always wins. Otherwise the last QSO's precise
+    // locator beats the coarse cty.dat entity centroid the provider block set — so
+    // a French call resolves to its real JNxx, not the country's JN16 centroid.
+    const adoptLastGrid = !ue.has('grid') && empty(r?.grid) && !!last.grid;
+    if (adoptLastGrid) setGrid(last.grid);
+    setDetails((d) => {
+      // When we adopt the last QSO's locator, take its coordinates too (derive them
+      // from the grid if that QSO didn't store any) so the map + saved record match.
+      let lat = d.lat, lon = d.lon;
+      if (adoptLastGrid) {
+        if (last.lat != null && last.lon != null) { lat = last.lat; lon = last.lon; }
+        else { const ll = gridToLatLon(last.grid); if (ll) { lat = ll.lat; lon = ll.lon; } }
+      } else {
+        lat = d.lat ?? (last.lat ?? undefined);
+        lon = d.lon ?? (last.lon ?? undefined);
+      }
+      return {
         ...d,
         address: d.address || last.address || '',
         state:   d.state   || last.state   || '',
         cnty:    d.cnty    || last.cnty    || '',
-      lat:     d.lat     ?? (last.lat ?? undefined),
-      lon:     d.lon     ?? (last.lon ?? undefined),
+        lat, lon,
         dxcc:    d.dxcc    ?? (last.dxcc || undefined),
         cqz:     d.cqz     ?? (last.cqz  || undefined),
         ituz:    d.ituz    ?? (last.ituz || undefined),
         cont:    d.cont    || last.cont  || '',
         email:   d.email   || last.email || '',
         qsl_via: d.qsl_via || last.qsl_via || '',
-    }));
-    if (last.grid || last.lat) setMapZoomSignal((n) => n + 1);
+      };
+    });
+    if (adoptLastGrid || last.grid || last.lat) setMapZoomSignal((n) => n + 1);
   }
   async function runLookup(call: string) {
     if (call !== lastLookedUpRef.current) resetAutoFill();