style(chat): continue to tweak animations around chat message insert

apps/flipcash/features/messenger/src/main/kotlin/com/flipcash/app/messenger/internal/screens/ChatAnimations.kt

@@ -0,0 +1,33 @@
+package com.flipcash.app.messenger.internal.screens
+
+import androidx.compose.animation.ExitTransition
+import androidx.compose.animation.core.Spring
+import androidx.compose.animation.core.SpringSpec
+import androidx.compose.animation.core.spring
+import androidx.compose.animation.fadeOut
+import androidx.compose.animation.shrinkVertically
+import androidx.compose.ui.unit.IntSize
+
+// All chat animation spring specs in one place.
+internal object ChatAnimations {
+    // Message bubble insertion — scale from 0.95 + opacity.
+    // Matches iOS insertionSpring: .spring(duration: 0.23, bounce: 0.27).
+    val insertion: SpringSpec<Float> = spring(dampingRatio = 0.73f, stiffness = 746f)
+
+    // Typing indicator entry/exit — scale from 0.95 + opacity.
+    val typingIndicator: SpringSpec<Float> = spring(dampingRatio = 0.73f, stiffness = Spring.StiffnessHigh)
+
+    // Action bar <-> composer swap — scale from 0.95 + opacity.
+    val composerSwap: SpringSpec<Float> = spring(dampingRatio = 0.69f, stiffness = Spring.StiffnessHigh)
+
+    // Delivered label appearance — scale from 0.95 + opacity.
+    // Matches iOS deliveredSpring: .spring(duration: 0.4, bounce: 0.12).
+    val delivered: SpringSpec<Float> = spring(dampingRatio = 0.88f, stiffness = 250f)
+
+    // Delivered -> Read label swap — scale + opacity.
+    val readSwap: SpringSpec<Float> = spring(dampingRatio = 0.74f, stiffness = Spring.StiffnessHigh)
+
+    // Receipt label exit when a new message is sent — fade out + collapse.
+    private val deliveredIntSize: SpringSpec<IntSize> = spring(dampingRatio = 0.88f, stiffness = 250f)
+    val receiptExit: ExitTransition = shrinkVertically(deliveredIntSize) + fadeOut(delivered)
+}

apps/flipcash/features/messenger/src/main/kotlin/com/flipcash/app/messenger/internal/screens/MessengerScreen.kt

@@ -1,8 +1,6 @@
 package com.flipcash.app.messenger.internal.screens
 
 import androidx.compose.animation.AnimatedContent
-import androidx.compose.animation.core.Spring
-import androidx.compose.animation.core.spring
 import androidx.compose.animation.fadeIn
 import androidx.compose.animation.fadeOut
 import androidx.compose.animation.scaleIn
@@ -49,7 +47,6 @@ import com.flipcash.app.core.contacts.DeviceContact
 import com.flipcash.app.messenger.internal.ChatViewModel
 import com.flipcash.app.messenger.internal.screens.components.MessageList
 import com.flipcash.features.messenger.R
-import com.flipcash.shared.chat.ui.SeparatorConfig
 import com.getcode.navigation.core.CodeNavigator
 import com.getcode.navigation.core.LocalCodeNavigator
 import com.getcode.theme.CodeTheme
@@ -191,11 +188,10 @@ private fun UserControlBottomBar(
             modifier = Modifier.padding(horizontal = CodeTheme.dimens.inset),
             targetState = state.typists.isNotEmpty(),
             transitionSpec = {
-                val insertSpec = spring<Float>(dampingRatio = 0.73f, stiffness = Spring.StiffnessHigh)
-                (scaleIn(insertSpec, initialScale = 0.95f, transformOrigin = TransformOrigin(0f, 0.5f))
-                    + fadeIn(insertSpec)) togetherWith
-                    (scaleOut(insertSpec, targetScale = 0.95f, transformOrigin = TransformOrigin(0f, 0.5f))
-                        + fadeOut(insertSpec))
+                (scaleIn(ChatAnimations.typingIndicator, initialScale = 0.95f, transformOrigin = TransformOrigin(0f, 0.5f))
+                    + fadeIn(ChatAnimations.typingIndicator)) togetherWith
+                    (scaleOut(ChatAnimations.typingIndicator, targetScale = 0.95f, transformOrigin = TransformOrigin(0f, 0.5f))
+                        + fadeOut(ChatAnimations.typingIndicator))
             }
         ) { show ->
             if (show) {
@@ -228,7 +224,7 @@ private fun UserControlBottomBar(
                 transitionSpec = {
                     // Action bar <-> composer swap
                     // Buttons: scale from 0.95 + opacity; Composer: opacity only
-                    val swapSpec = spring<Float>(dampingRatio = 0.69f, stiffness = Spring.StiffnessHigh)
+                    val swapSpec = ChatAnimations.composerSwap
                     when (targetState) {
                         ChatViewModel.UserState.Typing ->
                             // Composer fades in; buttons scale+fade out

apps/flipcash/features/messenger/src/main/kotlin/com/flipcash/app/messenger/internal/screens/components/MessageList.kt

@@ -1,7 +1,9 @@
 package com.flipcash.app.messenger.internal.screens.components
 
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.EnterTransition
 import androidx.compose.animation.core.animateFloatAsState
-import androidx.compose.animation.core.spring
+import com.flipcash.app.messenger.internal.screens.ChatAnimations
 import androidx.compose.foundation.gestures.detectTapGestures
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
@@ -139,22 +141,19 @@ internal fun MessageList(
             val isOutgoing = (item as? ChatListItem.ContentBubble)?.isFromSelf ?: false
 
             // Message insertion animation — scale from 0.95 + opacity with edge anchor.
-            // Tuned to match observed iOS timing (~500ms gradual fade-in).
             // Only animate genuinely new messages (index 0 after initial load).
             val shouldAnimate = index == 0 && hasLoaded && item.itemKey !in animatedKeys
             if (shouldAnimate) animatedKeys.add(item.itemKey)
             var appeared by remember(item.itemKey) { mutableStateOf(!shouldAnimate) }
             LaunchedEffect(Unit) { if (!appeared) appeared = true }
-            val insertionAlphaSpec = spring<Float>(dampingRatio = 0.86f, stiffness = 80f)
-            val insertionScaleSpec = spring<Float>(dampingRatio = 0.73f, stiffness = 300f)
             val insertionAlpha by animateFloatAsState(
                 targetValue = if (appeared) 1f else 0f,
-                animationSpec = insertionAlphaSpec,
+                animationSpec = ChatAnimations.insertion,
                 label = "insertAlpha",
             )
             val insertionScale by animateFloatAsState(
                 targetValue = if (appeared) 1f else 0.95f,
-                animationSpec = insertionScaleSpec,
+                animationSpec = ChatAnimations.insertion,
                 label = "insertScale",
             )
 
@@ -206,12 +205,18 @@ internal fun MessageList(
                             }
                             val showReceipt =
                                 shouldShowReceiptLabel(index, item, messages, otherReadPointer)
-                            if (showReceipt && effectiveStatus != null) {
-                                ReceiptLabel(
-                                    status = effectiveStatus,
-                                    readPointer = otherReadPointer,
-                                    animateEntrance = wasSending,
-                                )
+                            AnimatedVisibility(
+                                visible = showReceipt && effectiveStatus != null,
+                                enter = EnterTransition.None,
+                                exit = ChatAnimations.receiptExit,
+                            ) {
+                                if (effectiveStatus != null) {
+                                    ReceiptLabel(
+                                        status = effectiveStatus,
+                                        readPointer = otherReadPointer,
+                                        animateEntrance = wasSending,
+                                    )
+                                }
                             }
                         }
                     }
@@ -286,20 +291,17 @@ internal fun MessageList(
             }
     }
 
-    // opts out of the list maintaining
-    // scroll position when adding elements before the first item
-    // we are checking first visible item index to ensure
-    // the list doesn't shift when viewing scroll back
+    // Opt out of the list maintaining scroll position when adding
+    // elements before the first item. Only needed during initial load
+    // (to prevent starting at the ContactInfoContainer) and when
+    // scrolled back (to prevent shifting when pagination prepends).
+    // When at index 0, we do NOT call requestScrollToItem — doing so
+    // forces an instant reposition that causes a single-frame jitter
+    // when new messages are inserted. Instead, animateScrollToItem in
+    // the LaunchedEffect above handles smooth scrolling to new items.
     Snapshot.withoutReadObservation {
         if (!hasLoaded) {
-            // During initial load, always pin to index 0 (newest message)
-            // to prevent the list from starting at the ContactInfoContainer
             listState.requestScrollToItem(0, 0)
-        } else if (listState.firstVisibleItemIndex == 0) {
-            listState.requestScrollToItem(
-                index = listState.firstVisibleItemIndex,
-                scrollOffset = listState.firstVisibleItemScrollOffset
-            )
         }
     }
 }

apps/flipcash/features/messenger/src/main/kotlin/com/flipcash/app/messenger/internal/screens/components/ReceiptLabel.kt

@@ -3,9 +3,8 @@ package com.flipcash.app.messenger.internal.screens.components
 import android.text.format.DateFormat
 import androidx.compose.animation.AnimatedContent
 import androidx.compose.animation.AnimatedVisibility
-import androidx.compose.animation.core.Spring
 import androidx.compose.animation.core.snap
-import androidx.compose.animation.core.spring
+import com.flipcash.app.messenger.internal.screens.ChatAnimations
 import androidx.compose.animation.expandVertically
 import androidx.compose.animation.fadeIn
 import androidx.compose.animation.fadeOut
@@ -25,7 +24,6 @@ import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
-import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.stringResource
@@ -74,8 +72,7 @@ internal fun ReceiptLabel(
         }
     }
 
-    // Matches iOS deliveredSpring: .spring(duration: 0.4, bounce: 0.12)
-    val deliveredSpec = spring<Float>(dampingRatio = 0.88f, stiffness = 250f)
+    val deliveredSpec = ChatAnimations.delivered
 
     Box(
         modifier = modifier.padding(
@@ -94,7 +91,7 @@ internal fun ReceiptLabel(
             exit = shrinkVertically(snap()) + fadeOut(snap()),
         ) {
             // Delivered -> Read directional swap with scale
-            val readSwapSpec = spring<Float>(dampingRatio = 0.74f, stiffness = Spring.StiffnessHigh)
+            val readSwapSpec = ChatAnimations.readSwap
             AnimatedContent(
                 targetState = status,
                 transitionSpec = {