feat(counties): right-click to re-derive a US county from the ULS database

The automatic pass fills a blank county only, and deliberately: a value the
operator or QRZ supplied usually beats one derived from a ZIP code. That leaves
no way at all to correct a county already stored — and the Connecticut planning
regions are exactly that case. Every CT contact logged before that correction
holds a county the state abolished in 2022, and filling blanks never reaches
one of them.

So the new entry OVERWRITES, because it is asked for by hand on a chosen set of
rows precisely because the stored value is believed wrong. Only US entities are
touched, only callsigns the database holds, and only when the answer actually
differs — so re-running it on a mixed selection is safe and the count reported
is the number of counties that really changed. Award refs are re-materialised:
the county IS the reference for CQ USA-CA and the state for WAS.

The entry appears only once the database has been downloaded, and appears
without a restart when one finishes — an action that can only ever answer "no
database" is not worth a line in a menu this long.

changelog.json

@@ -2,8 +2,12 @@
   {
     "version": "0.25.6",
     "date": "",
-    "en": [],
-    "fr": []
+    "en": [
+      "Right-click: update the US county of the selected contacts from the ULS database, replacing a county since renamed or abolished."
+    ],
+    "fr": [
+      "Clic droit : mettre à jour le comté US des contacts sélectionnés depuis la base ULS, pour remplacer un comté renommé ou supprimé."
+    ]
   },
   {
     "version": "0.25.5",