Make the monitor window's divider draggable and remembered (#144) (#145)

The cluster and QSO monitor split its two tables at half the height, fixed:
the Compose port had left the JavaFX SplitPane out until a splitter existed.
SplitterPane exists now, so the monitor uses it and reads and writes the same
profile value the SplitPane did (GUIpnl_directedMSGWin_dividerpositionDefault,
default 0.8), so a profile gets its old position back. Each heading now sits
in the pane of its table, and the "DX cluster" heading is translated
(monitor.dxCluster).

Fixes #144.


Claude-Session: https://claude.ai/code/session_01AaorTymXfkXPm8yb4Btva7

Co-authored-by: Claude <noreply@anthropic.com>

app-desktop/src/main/kotlin/kst4contest/view/compose/MonitorWindow.kt

@@ -4,7 +4,6 @@ import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
-import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
@@ -17,10 +16,11 @@ import kst4contest.model.ClusterMessage
 /**
  * The cluster and QSO monitor.
  *
- * Two live tables, one above the other. This is the first window in which the table
- * carries data that changes while the operator watches, which is why the row identity
- * rules in DataTableState matter here and not in the settings window: in Etappe 2 the
- * visible defects all came from that coupling, not from the table itself.
+ * Two live tables, one above the other, with a divider the operator can drag. This
+ * is the first window in which the table carries data that changes while the operator
+ * watches, which is why the row identity rules in DataTableState matter here and not in
+ * the settings window: in Etappe 2 the visible defects all came from that coupling, not
+ * from the table itself.
  */
 object MonitorWindow {
 
@@ -44,6 +44,8 @@ object MonitorWindow {
     fun show(
         clusterTable: DataTableState<ClusterMessage>,
         qsoTable: DataTableState<ChatMessage>,
+        /** The divider between the two tables, remembered in the profile (#144). */
+        splitter: SplitterState,
         darkMode: Boolean,
         baseFontSizeSp: Float,
         /**
@@ -70,7 +72,7 @@ object MonitorWindow {
             heightDp = heightDp,
             onResized = onResized,
         ) { _ ->
-            MonitorContent(clusterTable, qsoTable)
+            MonitorContent(clusterTable, qsoTable, splitter)
         }
     }
 }
@@ -80,29 +82,31 @@ object MonitorWindow {
 internal fun MonitorContent(
     clusterTable: DataTableState<ClusterMessage>,
     qsoTable: DataTableState<ChatMessage>,
+    splitter: SplitterState,
 ) {
+    val strings = kst4contest.view.i18n.LocalStrings.current
+
     Surface(modifier = Modifier.fillMaxSize()) {
-        Column(modifier = Modifier.fillMaxSize().padding(4.dp)) {
-            Text("DX cluster", style = MaterialTheme.typography.titleSmall)
+        /*
+         * Each heading sits in the pane of its table, so dragging the divider moves the
+         * heading with the table it names rather than leaving it stranded above the other.
+         */
+        SplitterPane(
+            state = splitter,
+            orientation = SplitterOrientation.VERTICAL,
+            modifier = Modifier.fillMaxSize().padding(4.dp),
+            panes = listOf(
+                { MonitorPane(strings.monitorDxCluster, clusterTable) },
+                { MonitorPane(strings.messagesQsoOfTheOther, qsoTable) },
+            ),
+        )
+    }
+}
 
-            /*
-             * Half each, fixed. The JavaFX window used a SplitPane whose divider the
-             * operator could drag, and that position was stored; reproducing the
-             * gesture belongs with the station list of Etappe 5, where a split pane is
-             * unavoidable. Until then an even split is honest rather than a broken
-             * handle.
-             */
-            DataTableView(clusterTable, modifier = Modifier.weight(1f).fillMaxWidth())
-
-            HorizontalDivider(thickness = Density.HAIRLINE)
-
-            Text(
-                kst4contest.view.i18n.LocalStrings.current.messagesQsoOfTheOther,
-                style = MaterialTheme.typography.titleSmall,
-                modifier = Modifier.padding(top = 4.dp),
-            )
-
-            DataTableView(qsoTable, modifier = Modifier.weight(1f).fillMaxWidth())
-        }
+@Composable
+private fun <T> MonitorPane(heading: String, table: DataTableState<T>) {
+    Column(modifier = Modifier.fillMaxSize()) {
+        Text(heading, style = MaterialTheme.typography.titleSmall, modifier = Modifier.padding(top = 4.dp))
+        DataTableView(table, modifier = Modifier.weight(1f).fillMaxWidth())
     }
 }