fix(navigation): keep Downloads visible from launch

androidApp/src/androidMain/kotlin/org/siloserver/silo/android/ui/navigation/MobileDownloadVisibility.kt

@@ -18,11 +18,6 @@ fun hasLocalDownloadsForScope(
     profileId: String?,
 ): Boolean = scopedLocalDownloadBytes(storage, serverId, profileId) > 0L
 
-fun shouldShowDownloadsTab(
-    serverRecordCount: Int,
-    activeScopeLocalBytes: Long,
-): Boolean = serverRecordCount > 0 || activeScopeLocalBytes > 0L
-
 fun shouldStartOnDownloads(
     hasLocalDownloads: Boolean,
     isDeviceOnline: Boolean,

androidApp/src/androidMain/kotlin/org/siloserver/silo/android/ui/navigation/MobileMediaTabs.kt

@@ -1,22 +1,18 @@
 package org.siloserver.silo.android.ui.navigation
 
-import org.siloserver.silo.model.navigation.MediaModeCapabilities
-
 val Tab.isUtilityTab: Boolean
     get() = this == Tab.Downloads
 
-// Apple-aligned shell: Home · Libraries · For You · Calendar, plus a Downloads
-// tab only when the user has downloads. There is no per-media-type tab —
-// library content (video / audio / reading) is reached through the Libraries picker.
-fun visibleMobileTabs(
-    @Suppress("UNUSED_PARAMETER") capabilities: MediaModeCapabilities,
-    showDownloads: Boolean,
-): List<Tab> = buildList {
+// Apple-aligned shell: Home · Libraries · For You · Calendar · Downloads.
+// Downloads is a stable destination from the first frame; its screen owns the
+// empty and unavailable states instead of making the navigation bar reflow
+// after capability or local-record hydration completes.
+fun visibleMobileTabs(): List<Tab> = buildList {
     add(Tab.Home)
     add(Tab.Libraries)
     add(Tab.ForYou)
     add(Tab.Calendar)
-    if (showDownloads) add(Tab.Downloads)
+    add(Tab.Downloads)
 }
 
 fun fallbackMobileTab(

androidApp/src/androidMain/kotlin/org/siloserver/silo/android/ui/screens/MainScreen.kt

@@ -23,7 +23,6 @@ import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
-import androidx.compose.runtime.produceState
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.saveable.rememberSaveable
@@ -47,8 +46,6 @@ import org.siloserver.silo.android.ui.navigation.tabForRoute
 import org.siloserver.silo.android.ui.navigation.tabSwitchNavOptions
 import org.siloserver.silo.android.ui.navigation.bottomMostTabRoute
 import org.siloserver.silo.android.ui.navigation.fallbackMobileTab
-import org.siloserver.silo.android.ui.navigation.scopedLocalDownloadBytes
-import org.siloserver.silo.android.ui.navigation.shouldShowDownloadsTab
 import org.siloserver.silo.android.ui.navigation.visibleMobileTabs
 import org.siloserver.silo.android.ui.screens.calendar.CalendarScreen
 import org.siloserver.silo.android.ui.screens.home.HomeScreen
@@ -64,17 +61,12 @@ import org.siloserver.silo.android.ui.screens.recommendations.headerTitle
 import org.siloserver.silo.android.ui.screens.watchtogether.WatchTogetherMenuEntrySheet
 import org.siloserver.silo.cast.SiloCastPlaybackRequest
 import org.siloserver.silo.model.feature.CLIENT_WATCH_TOGETHER_SURFACE_ENABLED
-import org.siloserver.silo.model.navigation.MediaMode
-import org.siloserver.silo.model.navigation.MediaModeCapabilities
-import org.siloserver.silo.model.navigation.mobileMediaModeCapabilities
 import org.siloserver.silo.model.feature.MetadataAiFeatureStore
 import org.siloserver.silo.model.feature.RequestsFeatureStore
 import org.siloserver.silo.common.network.ServerReachabilityMonitor
 import org.siloserver.silo.common.network.ServerReachabilityStatus
-import org.siloserver.silo.network.ApiResult
 import org.siloserver.silo.network.ServerRegistry
 import org.siloserver.silo.repository.AuthRepository
-import org.siloserver.silo.repository.PersonalDataRepository
 import org.siloserver.silo.viewmodel.HomeViewModel
 import kotlinx.coroutines.launch
 import org.koin.compose.koinInject
@@ -133,14 +125,6 @@ fun MainScreen(
     // reacts by scrolling back to the top.
     var homeScrollToTopTick by remember { mutableStateOf(0) }
 
-    // Downloads tab visibility: show whenever EITHER the server says there
-    // are records OR we have bytes on disk. The on-disk check is what makes
-    // the tab survive airplane mode — `repository.refresh()` returns an
-    // empty list when offline, but the downloaded files are still there
-    // and we want the user to reach them.
-    val personalDataRepository: PersonalDataRepository = koinInject()
-    val downloadsRepository: org.siloserver.silo.repository.DownloadsRepository = koinInject()
-    val downloadStorage: org.siloserver.silo.common.downloads.DownloadStorage = koinInject()
     val serverRegistry: ServerRegistry = koinInject()
     val authRepository: AuthRepository = koinInject()
     val reachabilityMonitor: ServerReachabilityMonitor = koinInject()
@@ -150,45 +134,10 @@ fun MainScreen(
     val requestsEnabled by requestsFeatureStore.isEnabled.collectAsState()
     val reachabilityScope = rememberCoroutineScope()
     val activeEntry by serverRegistry.activeEntry.collectAsState()
-    val mediaCapabilities by produceState(
-        initialValue = MediaModeCapabilities(
-            listOf(
-                MediaMode.Video,
-                MediaMode.Audio,
-                MediaMode.Reading,
-            ),
-        ),
-        personalDataRepository,
-    ) {
-        value = when (val result = personalDataRepository.listUserLibraries()) {
-            is ApiResult.Success -> result.data.mobileMediaModeCapabilities()
-            else -> value
-        }
-    }
-    val downloadRecords by downloadsRepository.records.collectAsState()
-    val activeScopeLocalBytes by produceState(
-        initialValue = 0L,
-        downloadRecords,
-        activeEntry?.id,
-        activeEntry?.profileId,
-        headerState.activeProfile?.id,
-    ) {
-        value = scopedLocalDownloadBytes(
-            storage = downloadStorage,
-            serverId = activeEntry?.id,
-            profileId = activeEntry?.profileId ?: headerState.activeProfile?.id,
-        )
-    }
-    val visibleTabs = remember(mediaCapabilities, downloadRecords, activeScopeLocalBytes) {
-        val hasAnyDownload = shouldShowDownloadsTab(
-            serverRecordCount = downloadRecords.size,
-            activeScopeLocalBytes = activeScopeLocalBytes,
-        )
-        visibleMobileTabs(
-            capabilities = mediaCapabilities,
-            showDownloads = hasAnyDownload,
-        )
-    }
+    // Keep the mobile shell stable while profile capabilities and local
+    // download records hydrate. DownloadsScreen handles empty/unavailable
+    // states without adding or removing a bottom-navigation destination.
+    val visibleTabs = remember { visibleMobileTabs() }
 
     // The shared top bar floats over content; its real height is the status-bar
     // inset plus the fixed bar body. Offset tab content by that so the bar can't

androidApp/src/androidUnitTest/kotlin/org/siloserver/silo/android/ui/navigation/MobileDownloadVisibilityTest.kt

@@ -25,13 +25,6 @@ class MobileDownloadVisibilityTest {
         assertTrue(hasLocalDownloadsForScope(storage, "srv1", "profA"))
     }
 
-    @Test
-    fun `download tab visibility uses records or active scoped local bytes`() {
-        assertFalse(shouldShowDownloadsTab(serverRecordCount = 0, activeScopeLocalBytes = 0L))
-        assertTrue(shouldShowDownloadsTab(serverRecordCount = 1, activeScopeLocalBytes = 0L))
-        assertTrue(shouldShowDownloadsTab(serverRecordCount = 0, activeScopeLocalBytes = 1L))
-    }
-
     @Test
     fun `startup routes to downloads when local media exists and server cannot be used`() {
         assertFalse(

androidApp/src/androidUnitTest/kotlin/org/siloserver/silo/android/ui/navigation/MobileMediaTabsTest.kt

@@ -1,58 +1,21 @@
 package org.siloserver.silo.android.ui.navigation
 
-import org.siloserver.silo.model.navigation.MediaMode
-import org.siloserver.silo.model.navigation.MediaModeCapabilities
 import kotlin.test.Test
 import kotlin.test.assertEquals
-import kotlin.test.assertFalse
 import kotlin.test.assertTrue
 
 class MobileMediaTabsTest {
 
-    // Apple-aligned shell: Home · Libraries · For You · Calendar, independent of which
-    // media types the libraries contain. Library content (video / audio /
-    // reading) is reached through the Libraries picker. Downloads only appears
-    // when the user has downloads.
-    private val baseLabels = listOf("Home", "Libraries", "For You", "Calendar")
+    // The mobile shell is fixed from its first frame; content and capability
+    // hydration must not insert a tab later and reflow the navigation bar.
+    private val fixedLabels = listOf("Home", "Libraries", "For You", "Calendar", "Downloads")
 
     @Test
-    fun fixedTabsAppendDownloadsWhenPresent() {
-        val tabs = visibleMobileTabs(
-            capabilities = MediaModeCapabilities(listOf(MediaMode.Video)),
-            showDownloads = true,
-        )
-
-        assertEquals(baseLabels + "Downloads", tabs.map { it.label })
-    }
-
-    @Test
-    fun tabsAreFixedRegardlessOfLibraryTypes() {
-        assertEquals(
-            baseLabels,
-            visibleMobileTabs(MediaModeCapabilities(listOf(MediaMode.Audio)), showDownloads = false)
-                .map { it.label },
-        )
-        assertEquals(
-            baseLabels,
-            visibleMobileTabs(MediaModeCapabilities(listOf(MediaMode.Reading)), showDownloads = false)
-                .map { it.label },
-        )
-        assertEquals(
-            baseLabels,
-            visibleMobileTabs(MediaModeCapabilities(emptyList()), showDownloads = false)
-                .map { it.label },
-        )
-    }
-
-    @Test
-    fun downloadsStaysHiddenWhenNoDownloadsExist() {
-        val tabs = visibleMobileTabs(
-            capabilities = MediaModeCapabilities(listOf(MediaMode.Video, MediaMode.Audio)),
-            showDownloads = false,
-        )
+    fun fixedTabsAlwaysIncludeDownloads() {
+        val tabs = visibleMobileTabs()
 
-        assertEquals(baseLabels, tabs.map { it.label })
-        assertFalse(Tab.Downloads in tabs)
+        assertEquals(fixedLabels, tabs.map { it.label })
+        assertTrue(Tab.Downloads in tabs)
     }
 
     @Test