Refactor TextSpinner dialog UI and improve layout consistency

Update the `SpinnerSelectionDialog` to use a more modern design with rounded corners and improved spacing. The dialog now disables platform default width to allow custom horizontal padding and ensures text content is centered properly within selection rows.

Changes:
- TextSpinner: Simplify option visibility check; remove unnecessary `Row` wrappers in `TitleExplainer` to rely on column alignment.
- SpinnerSelectionDialog: Increase corner radius to 24.dp; remove `HorizontalDivider` and border strokes for a cleaner look; wrap content in `CompositionLocalProvider` to stabilize density.
- Layout: Center-align items horizontally within the selection list and add consistent vertical padding.

app/src/main/java/com/greenart7c3/nostrsigner/ui/components/TextSpinner.kt

@@ -20,7 +20,6 @@
  */
 package com.greenart7c3.nostrsigner.ui.components
 
-import androidx.compose.foundation.BorderStroke
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.interaction.MutableInteractionSource
 import androidx.compose.foundation.layout.Arrangement
@@ -34,12 +33,12 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.itemsIndexed
 import androidx.compose.foundation.shape.RoundedCornerShape
-import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.OutlinedTextField
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.CompositionLocalProvider
 import androidx.compose.runtime.Immutable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
@@ -50,10 +49,13 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.focus.FocusRequester
 import androidx.compose.ui.focus.focusRequester
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.platform.LocalDensity
 import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.Density
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
 import androidx.compose.ui.window.Dialog
+import androidx.compose.ui.window.DialogProperties
 import kotlinx.collections.immutable.ImmutableList
 
 @Composable
@@ -112,13 +114,11 @@ fun TextSpinner(
         )
     }
 
-    if (optionsShowing) {
-        options.isNotEmpty().also {
-            SpinnerSelectionDialog(options = options, onDismiss = { optionsShowing = false }) {
-                currentText = options[it].title
-                optionsShowing = false
-                onSelect(it)
-            }
+    if (optionsShowing && options.isNotEmpty()) {
+        SpinnerSelectionDialog(options = options, onDismiss = { optionsShowing = false }) {
+            currentText = options[it].title
+            optionsShowing = false
+            onSelect(it)
         }
     }
 }
@@ -136,20 +136,10 @@ fun SpinnerSelectionDialog(
         onSelect = onSelect,
         onDismiss = onDismiss,
     ) { item ->
-        Row(
-            horizontalArrangement = Arrangement.Center,
-            modifier = Modifier.fillMaxWidth(),
-        ) {
-            Text(text = item.title, color = MaterialTheme.colorScheme.onSurface)
-        }
+        Text(text = item.title, color = MaterialTheme.colorScheme.onSurface)
         item.explainer?.let {
             Spacer(modifier = Modifier.height(5.dp))
-            Row(
-                horizontalArrangement = Arrangement.Start,
-                modifier = Modifier.fillMaxWidth(),
-            ) {
-                Text(text = it, color = Color.Gray, fontSize = 14.sp)
-            }
+            Text(text = it, color = Color.Gray, fontSize = 14.sp)
         }
     }
 }
@@ -162,36 +152,58 @@ fun <T> SpinnerSelectionDialog(
     onDismiss: () -> Unit,
     onRenderItem: @Composable (T) -> Unit,
 ) {
-    Dialog(onDismissRequest = onDismiss) {
+    Dialog(
+        onDismissRequest = onDismiss,
+        properties = DialogProperties(usePlatformDefaultWidth = false),
+    ) {
         Surface(
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(horizontal = 20.dp),
             color = MaterialTheme.colorScheme.background,
-            border = BorderStroke(0.25.dp, Color.LightGray),
-            shape = RoundedCornerShape(5.dp),
+            shape = RoundedCornerShape(24.dp),
         ) {
-            LazyColumn {
-                title?.let {
-                    item {
-                        Row(
-                            modifier = Modifier.fillMaxWidth().padding(16.dp, 16.dp),
-                            horizontalArrangement = Arrangement.Center,
-                        ) {
-                            Text(
-                                text = title,
-                                color = MaterialTheme.colorScheme.onSurface,
-                                fontWeight = FontWeight.Bold,
-                            )
+            CompositionLocalProvider(
+                LocalDensity provides Density(
+                    LocalDensity.current.density,
+                    1f,
+                ),
+            ) {
+                LazyColumn(
+                    modifier = Modifier.padding(vertical = 10.dp),
+                ) {
+                    title?.let {
+                        item {
+                            Row(
+                                modifier = Modifier
+                                    .fillMaxWidth()
+                                    .padding(16.dp),
+                                horizontalArrangement = Arrangement.Center,
+                                verticalAlignment = Alignment.CenterVertically,
+                            ) {
+                                Text(
+                                    text = title,
+                                    color = MaterialTheme.colorScheme.onSurface,
+                                    fontWeight = FontWeight.Bold,
+                                )
+                            }
                         }
-                        HorizontalDivider(color = Color.LightGray, thickness = 0.25.dp)
                     }
-                }
-                itemsIndexed(options) { index, item ->
-                    Row(
-                        modifier = Modifier.fillMaxWidth().clickable { onSelect(index) }.padding(16.dp, 16.dp),
-                    ) {
-                        Column { onRenderItem(item) }
-                    }
-                    if (index < options.lastIndex) {
-                        HorizontalDivider(color = Color.LightGray, thickness = 0.25.dp)
+                    itemsIndexed(options) { index, item ->
+                        Row(
+                            modifier = Modifier
+                                .fillMaxWidth()
+                                .clickable { onSelect(index) }
+                                .padding(16.dp),
+                            verticalAlignment = Alignment.CenterVertically,
+                        ) {
+                            Column(
+                                modifier = Modifier.weight(1f),
+                                horizontalAlignment = Alignment.CenterHorizontally,
+                            ) {
+                                onRenderItem(item)
+                            }
+                        }
                     }
                 }
             }