feat(map): grid QSO dialog Match button prefills the match page

- Grid-QSO dialog gains a Match action (radio-tower icon + label) in its
  header; tapping it navigates to the match page pre-filled with the tapped
  grid as the opposite station and a 24h time range, auto-starts the query,
  and scrolls the page straight to the time-range card.
- Every grid is now tappable (previously only worked grids opened the
  dialog); unworked grids show an empty QSO list instead of a hint.

feature/mutual/src/main/java/com/rtbishop/look4sat/feature/mutual/MutualScreen.kt

@@ -246,7 +246,7 @@ private fun MutualContent(
         }
 
         // Input form
-        item {
+        item(key = "stationInputs") {
             Column(
                 modifier = Modifier.fillMaxWidth(),
                 verticalArrangement = Arrangement.spacedBy(6.dp)
@@ -323,16 +323,21 @@ private fun MutualContent(
                         )
                     }
                 }
-
-                MatchSearchCard(
-                    hoursAhead = state.hoursAhead,
-                    isCalculating = state.isCalculating,
-                    onHoursAhead = onHoursAhead,
-                    onQuery = onQuery
-                )
             }
         }
 
+        // Time range + query card. Its own LazyColumn item so a prefill from
+        // the map (grid-QSO dialog "Match" button) can scroll the page exactly
+        // to the time-range selector.
+        item(key = "matchSearch") {
+            MatchSearchCard(
+                hoursAhead = state.hoursAhead,
+                isCalculating = state.isCalculating,
+                onHoursAhead = onHoursAhead,
+                onQuery = onQuery
+            )
+        }
+
         // Results
         itemsIndexed(state.mutualPasses) { index, pass ->
             val mutualData = MutualPassData(
@@ -364,6 +369,17 @@ private fun MutualContent(
             )
         }
     }
+
+    // Prefill from the map's grid-QSO dialog "Match" button: jump straight to
+    // the time-range card. Index accounts for the optional error card at the
+    // top (error = 0, station inputs = 1, time range = 2; else 1).
+    val matchSearchIndex = if (state.errorMessage != null) 2 else 1
+    LaunchedEffect(state.scrollToTimeRange, matchSearchIndex) {
+        if (state.scrollToTimeRange) {
+            listState.scrollToItem(matchSearchIndex)
+            viewModel.consumeScrollToTimeRange()
+        }
+    }
 }
 
 @Composable

feature/mutual/src/main/java/com/rtbishop/look4sat/feature/mutual/MutualViewModel.kt

@@ -55,7 +55,11 @@ data class MutualUiState(
     val hasSearched: Boolean = false,
     val selectedPassIndex: Int = -1,
     val isUtc: Boolean = false,
-    val errorMessage: String? = null
+    val errorMessage: String? = null,
+    // One-shot flag set by prefillMatchFromGrid() (map grid → Match button):
+    // the page scrolls to the time-range card, then consumeScrollToTimeRange()
+    // clears it.
+    val scrollToTimeRange: Boolean = false
 )
 
 class MutualViewModel(
@@ -183,6 +187,32 @@ class MutualViewModel(
     fun onHoursAhead(value: Int) = _uiState.update { it.copy(hoursAhead = value) }
     fun onSelectPass(index: Int) = _uiState.update { it.copy(selectedPassIndex = index) }
 
+    /**
+     * Pre-fill the match page for a target grid picked from the map's grid-QSO
+     * dialog ("Match" button): set the opposite-station grid (with its
+     * coordinates), reset the time range to 24h, flag the page to scroll
+     * straight to the time-range card, and start the query immediately so
+     * results are ready when the page opens.
+     */
+    fun prefillMatchFromGrid(grid: String) {
+        val g = grid.trim().uppercase()
+        val pos = qthToPosition(g)
+        _uiState.update {
+            it.copy(
+                stationBGrid = g,
+                stationBLat = pos?.let { p -> "%.4f".format(p.latitude) } ?: it.stationBLat,
+                stationBLon = pos?.let { p -> "%.4f".format(p.longitude) } ?: it.stationBLon,
+                hoursAhead = 24,
+                scrollToTimeRange = true
+            )
+        }
+        queryMutualPasses()
+    }
+
+    fun consumeScrollToTimeRange() {
+        _uiState.update { it.copy(scrollToTimeRange = false) }
+    }
+
     fun queryMutualPasses() {
         val state = _uiState.value