feat: add setting to hide the on-chain (Bitcoin) wallet

Some users don't want the on-chain wallet surfaced. Add a `showOnchainWallet`
UI preference (default true, so behavior is unchanged) that hides it across the
app when turned off:

- the "Bitcoin" card on the Wallet screen (OnchainSection)
- the on-chain chip on profiles (DisplayPaymentRailChips)
- the on-chain rail in the Send Payment screen

The flag lives in the existing UiSettings/UiSettingsFlow display-preferences
system (persisted to the shared-settings DataStore, alongside the other
show/hide profile toggles) and is exposed as a switch on the Profile UI
settings screen.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UM57Rq5iUPL1SGhzhzTusa

amethyst/src/main/java/com/vitorpamplona/amethyst/model/UiSettings.kt

@@ -58,6 +58,11 @@ data class UiSettings(
     val fontFamily: FontFamilyType = FontFamilyType.SYSTEM,
     val fontSize: FontSizeType = FontSizeType.NORMAL,
     val composeSignature: String = "",
+    // Whether the on-chain (Bitcoin/Taproot) wallet is shown across the app: the
+    // "Bitcoin" card on the wallet screen, the on-chain chip on profiles, and the
+    // on-chain rail in the Send Payment screen. Defaults to true (shown) so the
+    // behavior is unchanged for everyone who doesn't turn it off.
+    val showOnchainWallet: Boolean = true,
 )
 
 enum class ThemeType(

amethyst/src/main/java/com/vitorpamplona/amethyst/model/UiSettingsFlow.kt

@@ -58,6 +58,7 @@ class UiSettingsFlow(
     val fontFamily: MutableStateFlow<FontFamilyType> = MutableStateFlow(FontFamilyType.SYSTEM),
     val fontSize: MutableStateFlow<FontSizeType> = MutableStateFlow(FontSizeType.NORMAL),
     val composeSignature: MutableStateFlow<String> = MutableStateFlow(""),
+    val showOnchainWallet: MutableStateFlow<Boolean> = MutableStateFlow(true),
 ) {
     val listOfFlows: List<Flow<Any?>> =
         listOf<Flow<Any?>>(
@@ -90,6 +91,7 @@ class UiSettingsFlow(
             fontFamily,
             fontSize,
             composeSignature,
+            showOnchainWallet,
         )
 
     // emits at every change in any of the propertyes.
@@ -126,6 +128,7 @@ class UiSettingsFlow(
                 flows[26] as FontFamilyType,
                 flows[27] as FontSizeType,
                 flows[28] as String,
+                flows[29] as Boolean,
             )
         }
 
@@ -160,6 +163,7 @@ class UiSettingsFlow(
             fontFamily.value,
             fontSize.value,
             composeSignature.value,
+            showOnchainWallet.value,
         )
 
     fun update(torSettings: UiSettings): Boolean {
@@ -281,6 +285,10 @@ class UiSettingsFlow(
             composeSignature.tryEmit(torSettings.composeSignature)
             any = true
         }
+        if (showOnchainWallet.value != torSettings.showOnchainWallet) {
+            showOnchainWallet.tryEmit(torSettings.showOnchainWallet)
+            any = true
+        }
 
         return any
     }
@@ -335,6 +343,7 @@ class UiSettingsFlow(
                 MutableStateFlow(uiSettings.fontFamily),
                 MutableStateFlow(uiSettings.fontSize),
                 MutableStateFlow(uiSettings.composeSignature),
+                MutableStateFlow(uiSettings.showOnchainWallet),
             )
     }
 }

amethyst/src/main/java/com/vitorpamplona/amethyst/model/preferences/UISharedPreferences.kt

@@ -127,6 +127,7 @@ class UiSharedPreferences(
         val UI_FONT_FAMILY = stringPreferencesKey("ui.font_family")
         val UI_FONT_SIZE = stringPreferencesKey("ui.font_size")
         val UI_COMPOSE_SIGNATURE = stringPreferencesKey("ui.compose_signature")
+        val UI_SHOW_ONCHAIN_WALLET = booleanPreferencesKey("ui.show_onchain_wallet")
 
         suspend fun uiPreferences(context: Context): UiSettings? =
             try {
@@ -168,6 +169,7 @@ class UiSharedPreferences(
                     fontFamily = preferences[UI_FONT_FAMILY]?.let { FontFamilyType.valueOf(it) } ?: FontFamilyType.SYSTEM,
                     fontSize = preferences[UI_FONT_SIZE]?.let { FontSizeType.valueOf(it) } ?: FontSizeType.NORMAL,
                     composeSignature = preferences[UI_COMPOSE_SIGNATURE] ?: "",
+                    showOnchainWallet = preferences[UI_SHOW_ONCHAIN_WALLET] ?: true,
                 )
             } catch (e: Exception) {
                 if (e is CancellationException) throw e
@@ -221,6 +223,7 @@ class UiSharedPreferences(
                     preferences[UI_FONT_FAMILY] = sharedSettings.fontFamily.name
                     preferences[UI_FONT_SIZE] = sharedSettings.fontSize.name
                     preferences[UI_COMPOSE_SIGNATURE] = sharedSettings.composeSignature
+                    preferences[UI_SHOW_ONCHAIN_WALLET] = sharedSettings.showOnchainWallet
                 }
             } catch (e: Exception) {
                 if (e is CancellationException) throw e

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/profile/header/ProfilePaymentRailChips.kt

@@ -47,6 +47,7 @@ import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import com.vitorpamplona.amethyst.R
 import com.vitorpamplona.amethyst.commons.hashtags.Cashu
 import com.vitorpamplona.amethyst.commons.hashtags.CustomHashTagIcons
@@ -103,7 +104,9 @@ fun DisplayPaymentRailChips(
                 ?.target
                 ?.mintUrl
         }
-    val onchainAvailable = LocalCache.onchainBackend != null
+    val showOnchainWallet by accountViewModel.settings.uiSettingsFlow.showOnchainWallet
+        .collectAsStateWithLifecycle()
+    val onchainAvailable = showOnchainWallet && LocalCache.onchainBackend != null
 
     val address =
         remember(baseUser.pubkeyHex) {

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/profile/payment/SendPaymentScreen.kt

@@ -160,7 +160,11 @@ private fun SendPaymentLoaded(
     // Cheap read, intentionally not remembered: the chain backend is wired up
     // asynchronously at boot and a frozen `remember {}` would hide the
     // on-chain rail for the whole composition if the screen won the race.
-    val onchainAvailable = LocalCache.onchainBackend != null
+    // Also honors the user's "show on-chain wallet" preference — off hides the
+    // rail everywhere, matching the wallet screen and profile chips.
+    val showOnchainWallet by accountViewModel.settings.uiSettingsFlow.showOnchainWallet
+        .collectAsStateWithLifecycle()
+    val onchainAvailable = showOnchainWallet && LocalCache.onchainBackend != null
     // When navigated from a `bitcoin` payment target, the on-chain rail pays
     // that announced address directly (plain send, no NIP-BC receipt) instead
     // of the recipient's pubkey-derived Taproot address. Re-validated here in

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/settings/ProfileUiSettingsScreen.kt

@@ -92,6 +92,7 @@ fun ProfileUiSettingsContent(accountViewModel: AccountViewModel) {
     val showAppRecommendations by ui.showProfileAppRecommendations.collectAsStateWithLifecycle()
     val showZapReceived by ui.showProfileZapReceivedFeed.collectAsStateWithLifecycle()
     val showFollowers by ui.showProfileFollowersFeed.collectAsStateWithLifecycle()
+    val showOnchainWallet by ui.showOnchainWallet.collectAsStateWithLifecycle()
 
     Column(
         modifier =
@@ -136,6 +137,13 @@ fun ProfileUiSettingsContent(accountViewModel: AccountViewModel) {
         )
         HorizontalDivider(modifier = Modifier.padding(horizontal = Size20dp))
 
+        ProfileUiSwitchRow(
+            title = stringRes(R.string.profile_ui_setting_onchain_wallet),
+            checked = showOnchainWallet,
+            onCheckedChange = { ui.showOnchainWallet.tryEmit(it) },
+        )
+        HorizontalDivider(modifier = Modifier.padding(horizontal = Size20dp))
+
         Column(modifier = Modifier.padding(vertical = 12.dp, horizontal = Size20dp)) {
             GalleryChoice(ui)
         }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/wallet/WalletScreen.kt

@@ -103,6 +103,8 @@ fun WalletScreen(
     // the first composition pass. init() is idempotent — just sets refs.
     cashuWalletViewModel.init(accountViewModel)
 
+    val showOnchainWallet by accountViewModel.settings.uiSettingsFlow.showOnchainWallet
+        .collectAsState()
     val hasNwcWallet by walletViewModel.hasWalletSetup.collectAsState()
     val cashuWalletEvent by cashuWalletViewModel.walletEvent.collectAsState()
     val hasCashuWallet = cashuWalletEvent != null
@@ -147,11 +149,13 @@ fun WalletScreen(
         },
     ) { padding ->
         Column(modifier = Modifier.padding(padding)) {
-            OnchainSection(
-                accountViewModel = accountViewModel,
-                nav = nav,
-                modifier = Modifier.padding(horizontal = 16.dp, vertical = 8.dp),
-            )
+            if (showOnchainWallet) {
+                OnchainSection(
+                    accountViewModel = accountViewModel,
+                    nav = nav,
+                    modifier = Modifier.padding(horizontal = 16.dp, vertical = 8.dp),
+                )
+            }
             if (!hasWallet) {
                 NoWalletSetup(
                     modifier = Modifier,

amethyst/src/main/res/values/strings.xml

@@ -2608,6 +2608,7 @@
     <string name="profile_ui_setting_app_recommendations">App Recommendations</string>
     <string name="profile_ui_setting_zap_received_feed">Zap Received Feed</string>
     <string name="profile_ui_setting_followers_feed">Followers Feed</string>
+    <string name="profile_ui_setting_onchain_wallet">Bitcoin (on-chain) Wallet</string>
     <string name="reactions_settings">Reaction Row</string>
     <string name="reactions_settings_description">Configure which reaction buttons are shown, their order, and whether to display counters.</string>
     <string name="reactions_settings_enabled">Enabled</string>