fix(ime): use the keyboard-aware back handler in the post composers

The thread reply composer (and every other full-screen draft-saving editor)
still consumed back with a raw `BackHandler`, so `KeyboardAwareBackHandler` —
added for exactly this case — only protected the three chat composers.

Popping the screen while the keyboard is still up races the predictive-back
window animation against the IME close animation. When the window animation
wins, the IME `WindowInsetsAnimationCompat` is cancelled before its terminal
zero frame reaches Compose, the shared `WindowInsets.ime` holder stays
"animating", and every `Modifier.imePadding()` freezes at keyboard height —
the keyboard vanishes but its padding stays behind, even after leaving
the screen.

Switching these composers to `KeyboardAwareBackHandler` lets the first back
(or back-swipe) fall through to the system, which dismisses the keyboard with
its own animation that completes cleanly; the next back saves the draft and
pops as before. The top bar's cancel arrow remains an always-available exit.

Covers `ShortNotePostScreen` (which also backs `PollPostScreen`),
`GenericCommentPostScreen`, `LongFormPostScreen`, `NewProductScreen`,
`NewPublicMessageScreen`, `NewGoalScreen`, `NewWorkoutScreen` and
`AwardBadgeScreen`. `VoiceReplyScreen` keeps the plain handler — it has no
text input or `imePadding()`.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LfUMGWYu2uTSyh17JJonfN

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/nip22Comments/GenericCommentPostScreen.kt

@@ -20,7 +20,6 @@
  */
 package com.vitorpamplona.amethyst.ui.note.nip22Comments
 
-import androidx.activity.compose.BackHandler
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.horizontalScroll
 import androidx.compose.foundation.layout.Box
@@ -67,6 +66,7 @@ import com.vitorpamplona.amethyst.ui.actions.uploads.SelectFromGallery
 import com.vitorpamplona.amethyst.ui.actions.uploads.SelectedMedia
 import com.vitorpamplona.amethyst.ui.actions.uploads.TakePictureButton
 import com.vitorpamplona.amethyst.ui.actions.uploads.TakeVideoButton
+import com.vitorpamplona.amethyst.ui.navigation.bottombars.KeyboardAwareBackHandler
 import com.vitorpamplona.amethyst.ui.navigation.navs.Nav
 import com.vitorpamplona.amethyst.ui.navigation.topbars.PostingTopBar
 import com.vitorpamplona.amethyst.ui.note.BaseUserPicture
@@ -177,7 +177,7 @@ fun GenericCommentPostScreen(
 
     StrippingFailureDialog(postViewModel.strippingFailureConfirmation)
 
-    BackHandler {
+    KeyboardAwareBackHandler {
         accountViewModel.launchSigner {
             postViewModel.sendDraftSync()
             postViewModel.cancel()

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/badges/award/AwardBadgeScreen.kt

@@ -20,7 +20,6 @@
  */
 package com.vitorpamplona.amethyst.ui.screen.loggedIn.badges.award
 
-import androidx.activity.compose.BackHandler
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
@@ -52,6 +51,7 @@ import androidx.lifecycle.viewmodel.compose.viewModel
 import com.vitorpamplona.amethyst.R
 import com.vitorpamplona.amethyst.commons.ui.components.Nip05OrPubkeyLine
 import com.vitorpamplona.amethyst.model.User
+import com.vitorpamplona.amethyst.ui.navigation.bottombars.KeyboardAwareBackHandler
 import com.vitorpamplona.amethyst.ui.navigation.navs.INav
 import com.vitorpamplona.amethyst.ui.navigation.topbars.SavingTopBar
 import com.vitorpamplona.amethyst.ui.note.UserPicture
@@ -88,7 +88,7 @@ fun AwardBadgeScreen(
         onDispose { userSuggestions.reset() }
     }
 
-    BackHandler {
+    KeyboardAwareBackHandler {
         nav.popBack()
     }
 

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/discover/nip23LongForm/LongFormPostScreen.kt

@@ -20,7 +20,6 @@
  */
 package com.vitorpamplona.amethyst.ui.screen.loggedIn.discover.nip23LongForm
 
-import androidx.activity.compose.BackHandler
 import androidx.compose.foundation.BorderStroke
 import androidx.compose.foundation.border
 import androidx.compose.foundation.clickable
@@ -96,6 +95,7 @@ import com.vitorpamplona.amethyst.ui.actions.uploads.TakeVideoButton
 import com.vitorpamplona.amethyst.ui.components.MyAsyncImage
 import com.vitorpamplona.amethyst.ui.components.ThinPaddingTextField
 import com.vitorpamplona.amethyst.ui.components.markdown.RenderContentAsMarkdown
+import com.vitorpamplona.amethyst.ui.navigation.bottombars.KeyboardAwareBackHandler
 import com.vitorpamplona.amethyst.ui.navigation.navs.Nav
 import com.vitorpamplona.amethyst.ui.navigation.topbars.PostingTopBar
 import com.vitorpamplona.amethyst.ui.note.creators.contentWarning.ContentSensitivityExplainer
@@ -149,7 +149,7 @@ fun LongFormPostScreen(
 
     StrippingFailureDialog(postViewModel.strippingFailureConfirmation)
 
-    BackHandler {
+    KeyboardAwareBackHandler {
         accountViewModel.launchSigner {
             postViewModel.sendDraftSync()
             postViewModel.cancel()

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/discover/nip99Classifieds/NewProductScreen.kt

@@ -20,7 +20,6 @@
  */
 package com.vitorpamplona.amethyst.ui.screen.loggedIn.discover.nip99Classifieds
 
-import androidx.activity.compose.BackHandler
 import androidx.compose.foundation.horizontalScroll
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
@@ -53,6 +52,7 @@ import com.vitorpamplona.amethyst.ui.actions.uploads.SelectFromGallery
 import com.vitorpamplona.amethyst.ui.actions.uploads.SelectedMedia
 import com.vitorpamplona.amethyst.ui.actions.uploads.TakePictureButton
 import com.vitorpamplona.amethyst.ui.actions.uploads.TakeVideoButton
+import com.vitorpamplona.amethyst.ui.navigation.bottombars.KeyboardAwareBackHandler
 import com.vitorpamplona.amethyst.ui.navigation.navs.INav
 import com.vitorpamplona.amethyst.ui.navigation.navs.Nav
 import com.vitorpamplona.amethyst.ui.navigation.topbars.PostingTopBar
@@ -141,7 +141,7 @@ fun NewProductScreen(
 
     StrippingFailureDialog(postViewModel.strippingFailureConfirmation)
 
-    BackHandler {
+    KeyboardAwareBackHandler {
         accountViewModel.launchSigner {
             postViewModel.sendDraftSync()
             postViewModel.cancel()

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/home/ShortNotePostScreen.kt

@@ -23,7 +23,6 @@ package com.vitorpamplona.amethyst.ui.screen.loggedIn.home
 import android.annotation.SuppressLint
 import android.content.Intent
 import android.net.Uri
-import androidx.activity.compose.BackHandler
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.horizontalScroll
 import androidx.compose.foundation.layout.Arrangement
@@ -93,6 +92,7 @@ import com.vitorpamplona.amethyst.ui.actions.uploads.VoiceMessagePreview
 import com.vitorpamplona.amethyst.ui.components.OutlinedThinPaddingTextField
 import com.vitorpamplona.amethyst.ui.components.ThinPaddingTextField
 import com.vitorpamplona.amethyst.ui.components.getActivity
+import com.vitorpamplona.amethyst.ui.navigation.bottombars.KeyboardAwareBackHandler
 import com.vitorpamplona.amethyst.ui.navigation.navs.Nav
 import com.vitorpamplona.amethyst.ui.navigation.routes.Route
 import com.vitorpamplona.amethyst.ui.navigation.topbars.PostingTopBar
@@ -235,7 +235,7 @@ internal fun NewPostScreenInner(
 
     StrippingFailureDialog(postViewModel.strippingFailureConfirmation)
 
-    BackHandler {
+    KeyboardAwareBackHandler {
         accountViewModel.launchSigner {
             postViewModel.sendDraftSync()
             postViewModel.cancel()

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/home/nip75Goals/NewGoalScreen.kt

@@ -20,7 +20,6 @@
  */
 package com.vitorpamplona.amethyst.ui.screen.loggedIn.home.nip75Goals
 
-import androidx.activity.compose.BackHandler
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
@@ -48,6 +47,7 @@ import androidx.compose.ui.text.input.KeyboardType
 import androidx.compose.ui.unit.dp
 import androidx.lifecycle.viewmodel.compose.viewModel
 import com.vitorpamplona.amethyst.R
+import com.vitorpamplona.amethyst.ui.navigation.bottombars.KeyboardAwareBackHandler
 import com.vitorpamplona.amethyst.ui.navigation.navs.INav
 import com.vitorpamplona.amethyst.ui.navigation.navs.Nav
 import com.vitorpamplona.amethyst.ui.navigation.topbars.PostingTopBar
@@ -81,7 +81,7 @@ fun NewGoalScreen(
     accountViewModel: AccountViewModel,
     nav: INav,
 ) {
-    BackHandler {
+    KeyboardAwareBackHandler {
         goalViewModel.cancel()
         nav.popBack()
     }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/notifications/publicMessages/NewPublicMessageScreen.kt

@@ -20,7 +20,6 @@
  */
 package com.vitorpamplona.amethyst.ui.screen.loggedIn.notifications.publicMessages
 
-import androidx.activity.compose.BackHandler
 import androidx.compose.foundation.horizontalScroll
 import androidx.compose.foundation.layout.Arrangement.Absolute.spacedBy
 import androidx.compose.foundation.layout.Column
@@ -64,6 +63,7 @@ import com.vitorpamplona.amethyst.ui.actions.uploads.SelectFromGallery
 import com.vitorpamplona.amethyst.ui.actions.uploads.TakePictureButton
 import com.vitorpamplona.amethyst.ui.actions.uploads.TakeVideoButton
 import com.vitorpamplona.amethyst.ui.components.ThinPaddingTextField
+import com.vitorpamplona.amethyst.ui.navigation.bottombars.KeyboardAwareBackHandler
 import com.vitorpamplona.amethyst.ui.navigation.navs.INav
 import com.vitorpamplona.amethyst.ui.navigation.navs.Nav
 import com.vitorpamplona.amethyst.ui.navigation.topbars.PostingTopBar
@@ -134,7 +134,7 @@ fun NewPublicMessageScreen(
 
     StrippingFailureDialog(postViewModel.strippingFailureConfirmation)
 
-    BackHandler {
+    KeyboardAwareBackHandler {
         accountViewModel.launchSigner {
             postViewModel.sendDraftSync()
             postViewModel.cancel()

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/workouts/NewWorkoutScreen.kt

@@ -20,7 +20,6 @@
  */
 package com.vitorpamplona.amethyst.ui.screen.loggedIn.workouts
 
-import androidx.activity.compose.BackHandler
 import androidx.compose.animation.Crossfade
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
@@ -61,6 +60,7 @@ import com.vitorpamplona.amethyst.R
 import com.vitorpamplona.amethyst.commons.icons.symbols.Icon
 import com.vitorpamplona.amethyst.commons.icons.symbols.MaterialSymbol
 import com.vitorpamplona.amethyst.commons.icons.symbols.MaterialSymbols
+import com.vitorpamplona.amethyst.ui.navigation.bottombars.KeyboardAwareBackHandler
 import com.vitorpamplona.amethyst.ui.navigation.navs.INav
 import com.vitorpamplona.amethyst.ui.navigation.routes.Route
 import com.vitorpamplona.amethyst.ui.navigation.topbars.PostingTopBar
@@ -80,7 +80,7 @@ fun NewWorkoutScreen(
     postViewModel.init(accountViewModel)
     postViewModel.prefill(prefill)
 
-    BackHandler {
+    KeyboardAwareBackHandler {
         postViewModel.cancel()
         nav.popBack()
     }