feat(map): run the Match query before navigating to the mutual page

Tapping the grid-QSO dialog "Match" button now starts the pass query on
the map page and only navigates to the match page once it finishes, so the
page's first frame already contains the results — the time-range card at
the top and the pass curves right below, with no scroll flicker. The dialog
button shows a spinner and is disabled while calculating. A uiState
collector in MainScreen performs the actual navigation (still a push, so
the back gesture returns to the map). Failures/exceptions still navigate so
the user is never stuck on the map page.

feature/mutual/src/test/java/com/rtbishop/look4sat/feature/mutual/MutualMatchPrefillScrollTest.kt

@@ -146,6 +146,13 @@ class MutualMatchPrefillScrollTest {
         // ...and the target grid + 24h range pre-filled.
         org.junit.Assert.assertEquals("OL62", s.stationBGrid)
         org.junit.Assert.assertEquals(24, s.hoursAhead)
+        // ...and navigation to the match page is pending until the query done.
+        assertTrue("navigation should be pending", s.pendingNavigation)
+        // The early-return guard means the query finished immediately (no
+        // satellites): the map page must now be free to navigate.
+        org.junit.Assert.assertFalse("query finished -> not calculating", s.isCalculating)
+        vm.consumePendingNavigation()
+        org.junit.Assert.assertFalse("consume clears pending navigation", vm.uiState.value.pendingNavigation)
     }
 
     @Test