fix(ui): honor the v2 amount gap, cross-fade the accessory token

The gap above the v2 amount was never rendering. heightIn(max=) only
lifts the max constraint, and a bare Spacer has no intrinsic size, so it
measured to the minimum and collapsed — grid.x4 and grid.x8 produced an
identical 32dp, all of it AmountArea's own row. height() fixes both
bounds while still coercing into the incoming constraints, so the spacer
contributes its 40dp and continues to give way on a short screen.

The token chip in the accessory row also cross-fades now, with a size
transform to carry the width change between currency names, so returning
from the picker reads as the control changing rather than a hard cut.

Author: bmc08gt

apps/flipcash/core-ui/src/main/kotlin/com/flipcash/app/core/ui/AmountWithKeypad.kt

@@ -6,7 +6,7 @@ import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
-import androidx.compose.foundation.layout.heightIn
+import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
@@ -129,13 +129,15 @@ fun LargeAmountField(
 
     Column(modifier = modifier.fillMaxSize()) {
         // The gap below the app bar, so the amount isn't jammed against the chrome — AmountArea's
-        // own row contributes 8dp on top of this. Capped rather than fixed: the grid keys off
-        // screen *width*, so a hard padding would survive intact on a short screen and squeeze the
-        // amount instead. Letting it give way keeps the 74sp digits legible on small devices.
+        // own row contributes 8dp on top of this. height() rather than heightIn(max=): the latter
+        // only lifts the max constraint, and a bare Spacer has no intrinsic size, so it measures to
+        // the minimum and collapses to nothing. height() fixes both bounds, and still coerces into
+        // the incoming constraints — so on a screen too short to grant the weighted share it gives
+        // way rather than squeezing the 74sp digits.
         Spacer(
             modifier = Modifier
                 .weight(1f, fill = false)
-                .heightIn(max = CodeTheme.dimens.grid.x8)
+                .height(CodeTheme.dimens.grid.x8)
         )
         AmountArea(
             modifier = Modifier

apps/flipcash/features/tokens/src/main/kotlin/com/flipcash/app/tokens/internal/TokenSelectorRow.kt

@@ -1,5 +1,11 @@
 package com.flipcash.app.tokens.internal
 
+import androidx.compose.animation.AnimatedContent
+import androidx.compose.animation.SizeTransform
+import androidx.compose.animation.core.tween
+import androidx.compose.animation.fadeIn
+import androidx.compose.animation.fadeOut
+import androidx.compose.animation.togetherWith
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Row
@@ -52,13 +58,28 @@ private fun TokenSelectorRow(
             horizontalArrangement = Arrangement.spacedBy(CodeTheme.dimens.grid.x2),
             verticalAlignment = Alignment.CenterVertically,
         ) {
-            TokenIconWithName(
-                token = selected.token,
-                imageSize = CodeTheme.dimens.staticGrid.x6,
-                textStyle = CodeTheme.typography.textMedium,
-                spacing = CodeTheme.dimens.grid.x2,
-                displayName = { selected.displayName },
-            )
+            // Cross-fade the chip when the picker returns a different currency, so the swap reads
+            // as the same control changing rather than a hard cut. Keyed on the mint, not the whole
+            // TokenWithBalance — a balance tick would otherwise re-run the transition. The size
+            // transform carries the width change, since currency names differ in length.
+            AnimatedContent(
+                targetState = selected,
+                contentKey = { it.token.address },
+                transitionSpec = {
+                    fadeIn(tween(durationMillis = 180, delayMillis = 60))
+                        .togetherWith(fadeOut(tween(durationMillis = 120)))
+                        .using(SizeTransform(clip = false) { _, _ -> tween(durationMillis = 220) })
+                },
+                label = "selectedToken",
+            ) { token ->
+                TokenIconWithName(
+                    token = token.token,
+                    imageSize = CodeTheme.dimens.staticGrid.x6,
+                    textStyle = CodeTheme.typography.textMedium,
+                    spacing = CodeTheme.dimens.grid.x2,
+                    displayName = { token.displayName },
+                )
+            }
 
             Icon(
                 modifier = Modifier.size(CodeTheme.dimens.staticGrid.x4),