feat(map): worked-grid QSO counts and operated-grid selector

- QSO dialog: each callsign row shows 'n QSO'/'n QSOs' (plurals) centered
  between callsign and date, styled like the date.
- Grid mode + VUCC filter: top-left selector picks the operated grid the
  VUCC count is computed from (defaults to the most-worked grid), with a
  collapsible list of all operated grids; arrow style matches the QSO
  dialog rows.

core/presentation/src/main/res/values-zh/strings.xml

@@ -122,6 +122,10 @@
     <string name="map_visibility">能见度：%s</string>
     <!-- Worked-grid QSO dialog -->
     <string name="grid_qso_calls_count">%d 个呼号 · %d 次通联</string>
+    <plurals name="grid_qso_count">
+        <item quantity="one">%d QSO</item>
+        <item quantity="other">%d QSOs</item>
+    </plurals>
     <string name="grid_qso_first">首通</string>
     <string name="grid_qso_no_sat">卫星未知</string>
     <string name="map_visible">日照中</string>

core/presentation/src/main/res/values/strings.xml

@@ -147,6 +147,10 @@
     <string name="map_visibility">Visibility: %s</string>
     <!-- Worked-grid QSO dialog -->
     <string name="grid_qso_calls_count">%d callsigns · %d QSOs</string>
+    <plurals name="grid_qso_count">
+        <item quantity="one">%d QSO</item>
+        <item quantity="other">%d QSOs</item>
+    </plurals>
     <string name="grid_qso_first">First</string>
     <string name="grid_qso_no_sat">satellite unknown</string>
     <string name="map_visible">Visible</string>