Launcher mode: Gearslip as the home screen of a head unit or a dash tablet

Turned on under Settings > Connection, Gearslip's car screen fills the device's own
display as its home app. An All apps page opens any other app full screen, Back and
a head unit's keys work the car UI, and Phone hides on devices that can't call.
Phones never see Gearslip offered as a home app unless it's switched on.

gearslip/src/main/java/app/seb3thehacker/gearslip/car/AllAppsScreen.kt

@@ -0,0 +1,65 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.lazy.grid.GridCells
+import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
+import androidx.compose.foundation.lazy.grid.items
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.produceState
+import androidx.compose.runtime.remember
+import androidx.compose.ui.graphics.asImageBitmap
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import app.seb3thehacker.gearslip.R
+import app.seb3thehacker.gearslip.mirror.PhoneApp
+import app.seb3thehacker.gearslip.mirror.PhoneApps
+import androidx.core.graphics.drawable.toBitmap
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+
+/**
+ * Launcher mode's app drawer: every app on the device, A to Z, each opened full screen. Gearslip
+ * comes first, for its own settings, which the car UI only partly covers.
+ */
+@Composable
+fun AllAppsScreen() {
+    val context = LocalContext.current
+    val apps by produceState(initialValue = PhoneApps.cached() ?: emptyList(), context) {
+        value = PhoneApps.cached() ?: withContext(Dispatchers.IO) { PhoneApps.installed(context).also { PhoneApps.warm(context) } }
+    }
+    val gearslip = remember(context) {
+        val label = context.packageManager.getApplicationLabel(context.applicationInfo).toString()
+        val icon = runCatching { context.packageManager.getApplicationIcon(context.packageName).toBitmap(ICON_PX, ICON_PX).asImageBitmap() }
+        PhoneApp(context.packageName, label, icon.getOrNull())
+    }
+
+    Column(Modifier.fillMaxSize().padding(start = 20.dp, end = 20.dp, top = 12.dp)) {
+        ScreenHeader(stringResource(R.string.app_all_apps))
+        Spacer(Modifier.height(12.dp))
+        LazyVerticalGrid(
+            columns = GridCells.Adaptive(minSize = 108.dp),
+            modifier = Modifier.fillMaxSize(),
+            contentPadding = PaddingValues(bottom = 16.dp),
+            horizontalArrangement = Arrangement.spacedBy(12.dp),
+            verticalArrangement = Arrangement.spacedBy(12.dp),
+        ) {
+            item {
+                PhoneAppTile(gearslip) { LauncherMode.launch(context, context.packageName) }
+            }
+            items(apps.sortedBy { it.label.lowercase() }) { app ->
+                PhoneAppTile(app) { LauncherMode.launch(context, app.packageName) }
+            }
+        }
+    }
+}
+
+private const val ICON_PX = 128