The Android app updates itself from our Gitea releases; feed cards fade in instead of bouncing

- API: GET /app/android/latest reads the latest Gitea release (ANDROID_RELEASES_URL, optional token for a
  private repo) with the APK's SHA-256 from SHA256SUMS; GET /app/android/apk/:name streams that APK.
- App (modules/updater): downloads in the background, checks the SHA-256, and installs through
  PackageInstaller: quietly once when leaving the app (Android 12+), otherwise from the feed banner or
  Settings > App version. F-Droid builds leave it out and drop the install permissions.
- CI: the release notes come from the fastlane changelog; the app shows the part above ---.
- Settings: Create-account and Link Spotify buttons for Last.fm and ListenBrainz.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/mobile/src/app/(tabs)/index.tsx

@@ -1,7 +1,7 @@
 import { router } from 'expo-router';
 import { useEffect, useState } from 'react';
 import { Pressable, RefreshControl, ScrollView, StyleSheet, Text, View } from 'react-native';
-import Animated, { FadeInDown, LinearTransition } from 'react-native-reanimated';
+import Animated, { FadeIn, LinearTransition } from 'react-native-reanimated';
 import { SafeAreaView } from 'react-native-safe-area-context';
 import useSWR, { useSWRConfig } from 'swr';
 import { sortFeed, type ConnectionDTO, type FeedItemDTO, type FollowListDTO, type ProfileDTO } from '@musicshare/shared';
@@ -10,6 +10,7 @@ import { ActivityBell } from '@/components/ActivityBell';
 import { Avatar } from '@/components/Avatar';
 import { NowPlayingCard } from '@/components/NowPlayingCard';
 import { RelinkReminder } from '@/components/RelinkReminder';
+import { UpdateBanner } from '@/components/UpdateBanner';
 import { SharingControls } from '@/components/SharingControls';
 import { Body, Button, Card, Title } from '@/components/ui';
 import { api } from '@/lib/api';
@@ -84,9 +85,9 @@ export default function FeedScreen() {
   return (
     <SafeAreaView style={styles.safe} edges={['top']}>
       <AmbientBackground />
-      {/* Cards rise in on load and glide to new positions when someone pins or starts playing. */}
+      {/* Cards fade in and slide to new positions when someone pins or starts playing. */}
       <Animated.FlatList
-        itemLayoutAnimation={LinearTransition.springify().damping(18)}
+        itemLayoutAnimation={LinearTransition.duration(200)}
         data={feed ?? []}
         keyExtractor={(item) => item.user.id}
         contentContainerStyle={styles.list}
@@ -97,6 +98,7 @@ export default function FeedScreen() {
               <Text style={styles.brand}>musicshare</Text>
               <ActivityBell />
             </View>
+            <UpdateBanner />
             <SharingControls compact />
             <RelinkReminder />
             {offerAppleMusic && (
@@ -160,8 +162,8 @@ export default function FeedScreen() {
             </View>
           ) : null
         }
-        renderItem={({ item, index }) => (
-          <Animated.View entering={FadeInDown.delay(Math.min(index, 8) * 60).springify().damping(16)}>
+        renderItem={({ item }) => (
+          <Animated.View entering={FadeIn.duration(180)}>
             <NowPlayingCard
               np={item}
               preferred={me?.preferredService}