Add window width class and TV focus restoration

Introduce a runtime WindowWidthClass (Compact/Medium/Expanded) provided at
the app root and use it to drive responsive grid columns on Discover and
Library. Add initial focus, focusRestorer, and focusGroup to the TV home and
sidebar, apply focusRestorer to the shared Discover/Library grids, and
strengthen the focused card highlight.

shared/src/commonMain/kotlin/com/fluxa/app/shared/FluxaAppHost.kt

@@ -1,6 +1,9 @@
 package com.fluxa.app.shared
 
+import androidx.compose.foundation.layout.BoxWithConstraints
+import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.CompositionLocalProvider
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
@@ -356,6 +359,13 @@ fun FluxaAppHost(
         }
     }
 
+    BoxWithConstraints(modifier = Modifier.fillMaxSize()) {
+        val widthClass = if (deviceType == com.fluxa.app.ui.catalog.DeviceType.TV) {
+            com.fluxa.app.ui.catalog.WindowWidthClass.Expanded
+        } else {
+            com.fluxa.app.ui.catalog.widthClassFor(maxWidth)
+        }
+        CompositionLocalProvider(com.fluxa.app.ui.catalog.LocalWindowWidthClass provides widthClass) {
     FluxaApp(
         state = appState.uiState,
         deviceType = deviceType,
@@ -557,4 +567,6 @@ fun FluxaAppHost(
         showNavigationBar = showNavigationBar,
         modifier = modifier
     )
+        }
+    }
 }

shared/src/commonMain/kotlin/com/fluxa/app/shared/TvSidebarNav.kt

@@ -1,7 +1,10 @@
+@file:OptIn(androidx.compose.foundation.ExperimentalFoundationApi::class)
+
 package com.fluxa.app.shared
 
 import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
+import androidx.compose.foundation.focusGroup
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
@@ -26,6 +29,7 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
+import androidx.compose.ui.focus.focusRestorer
 import androidx.compose.ui.focus.onFocusChanged
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.vector.ImageVector
@@ -59,7 +63,9 @@ fun TvSidebarNav(
             .fillMaxHeight()
             .width(84.dp)
             .background(Color.Black.copy(alpha = 0.55f))
-            .padding(vertical = 24.dp),
+            .padding(vertical = 24.dp)
+            .focusGroup()
+            .focusRestorer(),
         verticalArrangement = Arrangement.spacedBy(8.dp, Alignment.CenterVertically)
     ) {
         TvSidebarItems.forEach { item ->

shared/src/commonMain/kotlin/com/fluxa/app/shared/feature/catalog/TvCatalogHomeScreen.kt

@@ -1,3 +1,5 @@
+@file:OptIn(androidx.compose.foundation.ExperimentalFoundationApi::class)
+
 package com.fluxa.app.shared.feature.catalog
 
 import androidx.compose.foundation.background
@@ -18,10 +20,16 @@ import androidx.compose.foundation.lazy.items
 import androidx.compose.material3.Text
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.ArrowForward
+import androidx.compose.foundation.focusGroup
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.remember
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
+import androidx.compose.ui.focus.FocusRequester
+import androidx.compose.ui.focus.focusRequester
+import androidx.compose.ui.focus.focusRestorer
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextOverflow
@@ -38,17 +46,25 @@ fun TvCatalogHomeScreen(
     language: String? = null,
     modifier: Modifier = Modifier
 ) {
+    val columnFocus = remember { FocusRequester() }
     Box(modifier = modifier.fillMaxSize()) {
         if (state.rows.isEmpty()) {
             TvCatalogHomeLoading(Modifier.fillMaxSize())
         } else {
+            LaunchedEffect(Unit) { runCatching { columnFocus.requestFocus() } }
             LazyColumn(
-                modifier = Modifier.fillMaxSize(),
+                modifier = Modifier
+                    .fillMaxSize()
+                    .focusRequester(columnFocus)
+                    .focusRestorer(),
                 contentPadding = PaddingValues(top = 44.dp, bottom = 64.dp),
                 verticalArrangement = Arrangement.spacedBy(30.dp)
             ) {
                 items(state.rows, key = { it.id }) { row ->
-                    Column(verticalArrangement = Arrangement.spacedBy(14.dp)) {
+                    Column(
+                        modifier = Modifier.focusGroup(),
+                        verticalArrangement = Arrangement.spacedBy(14.dp)
+                    ) {
                         Text(
                             text = row.title,
                             color = Color.White,
@@ -59,6 +75,7 @@ fun TvCatalogHomeScreen(
                             modifier = Modifier.padding(horizontal = 58.dp)
                         )
                         LazyRow(
+                            modifier = Modifier.focusRestorer(),
                             contentPadding = PaddingValues(horizontal = 58.dp),
                             horizontalArrangement = Arrangement.spacedBy(20.dp)
                         ) {

shared/src/commonMain/kotlin/com/fluxa/app/shared/feature/discover/DiscoverScreen.kt

@@ -1,8 +1,11 @@
+@file:OptIn(androidx.compose.foundation.ExperimentalFoundationApi::class)
+
 package com.fluxa.app.shared.feature.discover
 
 import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.horizontalScroll
+import androidx.compose.ui.focus.focusRestorer
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
@@ -59,6 +62,8 @@ import com.fluxa.app.shared.feature.search.SearchResultRows
 import com.fluxa.app.shared.feature.search.SearchResults
 import com.fluxa.app.ui.catalog.CatalogCard
 import com.fluxa.app.ui.catalog.FluxaColors
+import com.fluxa.app.ui.catalog.LocalWindowWidthClass
+import com.fluxa.app.ui.catalog.gridColumns
 
 @Composable
 fun DiscoverScreen(
@@ -141,8 +146,8 @@ fun DiscoverScreen(
                     }
                     LazyVerticalGrid(
                         state = gridState,
-                        columns = GridCells.Fixed(3),
-                        modifier = Modifier.weight(1f).fillMaxWidth(),
+                        columns = GridCells.Fixed(LocalWindowWidthClass.current.gridColumns()),
+                        modifier = Modifier.weight(1f).fillMaxWidth().focusRestorer(),
                         contentPadding = PaddingValues(bottom = 120.dp),
                         horizontalArrangement = Arrangement.spacedBy(12.dp),
                         verticalArrangement = Arrangement.spacedBy(16.dp)
@@ -201,7 +206,7 @@ private fun DiscoverSearchField(
 @Composable
 private fun DiscoverSkeletonGrid(modifier: Modifier = Modifier) {
     LazyVerticalGrid(
-        columns = GridCells.Fixed(3),
+        columns = GridCells.Fixed(LocalWindowWidthClass.current.gridColumns()),
         modifier = modifier.fillMaxWidth(),
         contentPadding = PaddingValues(bottom = 120.dp),
         horizontalArrangement = Arrangement.spacedBy(12.dp),

shared/src/commonMain/kotlin/com/fluxa/app/shared/feature/library/LibraryScreen.kt

@@ -1,3 +1,5 @@
+@file:OptIn(androidx.compose.foundation.ExperimentalFoundationApi::class)
+
 package com.fluxa.app.shared.feature.library
 
 import androidx.compose.foundation.background
@@ -43,6 +45,7 @@ import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.focus.FocusRequester
+import androidx.compose.ui.focus.focusRestorer
 import androidx.compose.ui.focus.focusRequester
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.text.font.FontWeight
@@ -55,6 +58,8 @@ import com.fluxa.app.shared.feature.discover.DiscoverFilterOptionUiModel
 import com.fluxa.app.shared.image.FluxaRemoteImage
 import com.fluxa.app.ui.catalog.CatalogCard
 import com.fluxa.app.ui.catalog.FluxaColors
+import com.fluxa.app.ui.catalog.LocalWindowWidthClass
+import com.fluxa.app.ui.catalog.gridColumns
 
 @Composable
 fun LibraryScreen(
@@ -265,11 +270,11 @@ private fun LibraryItemGrid(
         return
     }
     LazyVerticalGrid(
-        columns = GridCells.Fixed(3),
+        columns = GridCells.Fixed(LocalWindowWidthClass.current.gridColumns()),
         contentPadding = PaddingValues(start = 16.dp, end = 16.dp, top = 12.dp, bottom = 120.dp),
         horizontalArrangement = Arrangement.spacedBy(12.dp),
         verticalArrangement = Arrangement.spacedBy(16.dp),
-        modifier = Modifier.fillMaxSize()
+        modifier = Modifier.fillMaxSize().focusRestorer()
     ) {
         items(items, key = { "${it.type}:${it.id}" }) { item ->
             CatalogCard(model = item.card.copy(showTitleBar = true), onClick = { onItemSelected(item) })

shared/src/commonMain/kotlin/com/fluxa/app/ui/catalog/CatalogCard.kt

@@ -72,8 +72,8 @@ fun CatalogCard(
             .then(
                 if (focused) {
                     Modifier
-                        .scale(1.05f)
-                        .border(2.dp, Color.White, RoundedCornerShape(8.dp))
+                        .scale(1.1f)
+                        .border(3.dp, Color.White, RoundedCornerShape(8.dp))
                 } else {
                     Modifier
                 }

shared/src/commonMain/kotlin/com/fluxa/app/ui/catalog/WindowWidthClass.kt

@@ -0,0 +1,21 @@
+package com.fluxa.app.ui.catalog
+
+import androidx.compose.runtime.compositionLocalOf
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.dp
+
+enum class WindowWidthClass { Compact, Medium, Expanded }
+
+val LocalWindowWidthClass = compositionLocalOf { WindowWidthClass.Compact }
+
+fun widthClassFor(maxWidth: Dp): WindowWidthClass = when {
+    maxWidth < 600.dp -> WindowWidthClass.Compact
+    maxWidth < 840.dp -> WindowWidthClass.Medium
+    else -> WindowWidthClass.Expanded
+}
+
+fun WindowWidthClass.gridColumns(): Int = when (this) {
+    WindowWidthClass.Compact -> 3
+    WindowWidthClass.Medium -> 5
+    WindowWidthClass.Expanded -> 7
+}