feat: add offline wake-word detection with sherpa-onnx

- Integrate sherpa-onnx for local "Computer" wake-word detection
- Add foreground service (microphone type) for continued listening across apps
- Request RECORD_AUDIO, POST_NOTIFICATIONS, and foreground service permissions
- Download and verify pinned sherpa-onnx model (17 MB) on first enable
- Update LauncherViewModel with wake-word state and controller
- Add WorkManager and commons-compress dependencies for model extraction
- Update README with wake-word feature details and limitations

app/src/main/java/com/ambient/launcher/MainActivity.kt

@@ -1,10 +1,12 @@
 package com.ambient.launcher
 
+import android.Manifest
 import android.app.role.RoleManager
 import android.content.BroadcastReceiver
 import android.content.Context
 import android.content.Intent
 import android.content.IntentFilter
+import android.content.pm.PackageManager
 import android.content.res.Configuration
 import android.os.BatteryManager
 import android.os.Build
@@ -56,6 +58,7 @@ import androidx.compose.material.icons.filled.Close
 import androidx.compose.material.icons.filled.Home
 import androidx.compose.material.icons.filled.Image as ImageIcon
 import androidx.compose.material.icons.filled.Info
+import androidx.compose.material.icons.filled.Mic
 import androidx.compose.material.icons.filled.Refresh
 import androidx.compose.material.icons.filled.Search
 import androidx.compose.material.icons.filled.Settings
@@ -72,6 +75,7 @@ import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.FilledIconButton
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
+import androidx.compose.material3.LinearProgressIndicator
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.NavigationRail
 import androidx.compose.material3.NavigationRailItem
@@ -116,6 +120,7 @@ import androidx.compose.ui.window.Dialog
 import androidx.compose.ui.window.DialogProperties
 import androidx.core.graphics.drawable.toBitmap
 import androidx.core.net.toUri
+import androidx.core.content.ContextCompat
 import androidx.core.view.WindowCompat
 import androidx.core.view.WindowInsetsCompat
 import androidx.core.view.WindowInsetsControllerCompat
@@ -156,6 +161,16 @@ class MainActivity : ComponentActivity() {
         }
     }
 
+    override fun onStart() {
+        super.onStart()
+        viewModel.setLauncherVisible(true)
+    }
+
+    override fun onStop() {
+        viewModel.setLauncherVisible(false)
+        super.onStop()
+    }
+
     private fun requestHomeRole() {
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
             val roleManager = getSystemService(RoleManager::class.java)
@@ -234,7 +249,12 @@ private fun AmbientLauncherApp(
                 updateSettings = viewModel::updateSettings,
                 setLocalFolder = viewModel::setLocalFolder,
                 refreshWeather = viewModel::refreshWeather,
-                requestHomeRole = requestHomeRole
+                requestHomeRole = requestHomeRole,
+                setWakeWordEnabled = viewModel::setWakeWordEnabled,
+                setWakeWordSensitivity = viewModel::setWakeWordSensitivity,
+                pauseWakeWord = viewModel::pauseWakeWord,
+                resumeWakeWord = viewModel::resumeWakeWord,
+                testWakeWord = viewModel::testWakeWord
             )
         }
     }
@@ -642,7 +662,7 @@ private fun AppTile(
     }
 }
 
-private enum class SettingsSection { DISPLAY, WEATHER, ROUTINES, APPS, ACCESS }
+private enum class SettingsSection { DISPLAY, WEATHER, ROUTINES, VOICE, APPS, ACCESS }
 
 @Composable
 private fun SettingsScreen(
@@ -651,7 +671,12 @@ private fun SettingsScreen(
     updateSettings: ((LauncherSettings) -> LauncherSettings) -> Unit,
     setLocalFolder: (String) -> Unit,
     refreshWeather: () -> Unit,
-    requestHomeRole: () -> Unit
+    requestHomeRole: () -> Unit,
+    setWakeWordEnabled: (Boolean) -> Unit,
+    setWakeWordSensitivity: (Int) -> Unit,
+    pauseWakeWord: () -> Unit,
+    resumeWakeWord: () -> Unit,
+    testWakeWord: () -> Unit
 ) {
     var section by rememberSaveable { mutableStateOf(SettingsSection.DISPLAY) }
     val context = LocalContext.current
@@ -677,6 +702,7 @@ private fun SettingsScreen(
                     SettingsSection.DISPLAY -> ImageIcon
                     SettingsSection.WEATHER -> Icons.Default.Refresh
                     SettingsSection.ROUTINES -> Icons.Default.VolumeUp
+                    SettingsSection.VOICE -> Icons.Default.Mic
                     SettingsSection.APPS -> Icons.Default.Apps
                     SettingsSection.ACCESS -> Icons.Default.Info
                 }
@@ -701,6 +727,14 @@ private fun SettingsScreen(
                     refreshWeather
                 )
                 SettingsSection.ROUTINES -> RoutineSettings(state.settings, updateSettings)
+                SettingsSection.VOICE -> VoiceSettings(
+                    state = state,
+                    setEnabled = setWakeWordEnabled,
+                    setSensitivity = setWakeWordSensitivity,
+                    pause = pauseWakeWord,
+                    resume = resumeWakeWord,
+                    test = testWakeWord
+                )
                 SettingsSection.APPS -> ApplicationsSettings(state, updateSettings)
                 SettingsSection.ACCESS -> AccessSettings(requestHomeRole)
             }
@@ -898,6 +932,124 @@ private fun RoutineSettings(
     }
 }
 
+@Composable
+private fun VoiceSettings(
+    state: LauncherUiState,
+    setEnabled: (Boolean) -> Unit,
+    setSensitivity: (Int) -> Unit,
+    pause: () -> Unit,
+    resume: () -> Unit,
+    test: () -> Unit
+) = SettingsPage("Voice assistant") {
+    val context = LocalContext.current
+    val requiredPermissions = remember {
+        buildList {
+            add(Manifest.permission.RECORD_AUDIO)
+            if (Build.VERSION.SDK_INT >= 33) add(Manifest.permission.POST_NOTIFICATIONS)
+        }.toTypedArray()
+    }
+    val permissionLauncher = rememberLauncherForActivityResult(
+        ActivityResultContracts.RequestMultiplePermissions()
+    ) { results ->
+        if (requiredPermissions.all { results[it] == true }) setEnabled(true)
+    }
+    fun permissionsGranted(): Boolean = requiredPermissions.all {
+        ContextCompat.checkSelfPermission(context, it) == PackageManager.PERMISSION_GRANTED
+    }
+
+    SettingsCard(
+        "Listen for “Computer”",
+        "Detection stays on-device. Continued listening in other apps requires a persistent " +
+            "notification and Android’s microphone privacy indicator."
+    ) {
+        Switch(
+            checked = state.settings.wakeWord.enabled,
+            onCheckedChange = { enabled ->
+                if (!enabled) {
+                    setEnabled(false)
+                } else if (permissionsGranted()) {
+                    setEnabled(true)
+                } else {
+                    permissionLauncher.launch(requiredPermissions)
+                }
+            }
+        )
+        Text(
+            when (state.wakeWord.state) {
+                WakeWordState.DISABLED -> "Disabled"
+                WakeWordState.DOWNLOADING -> "Downloading model"
+                WakeWordState.INSTALLING -> "Installing model"
+                WakeWordState.READY -> "Ready"
+                WakeWordState.LISTENING -> "Listening"
+                WakeWordState.PAUSED -> "Paused"
+                WakeWordState.MICROPHONE_BUSY -> "Microphone busy; retrying"
+                WakeWordState.ERROR -> "Error"
+            },
+            fontWeight = FontWeight.SemiBold
+        )
+        if (state.wakeWord.message.isNotBlank()) {
+            Text(state.wakeWord.message, color = MaterialTheme.colorScheme.onSurfaceVariant)
+        }
+        if (
+            state.wakeWord.modelState == ModelInstallState.DOWNLOADING ||
+            state.wakeWord.modelState == ModelInstallState.INSTALLING
+        ) {
+            LinearProgressIndicator(
+                progress = { state.wakeWord.installProgress / 100f },
+                modifier = Modifier.fillMaxWidth()
+            )
+            Text("${state.wakeWord.installProgress}%")
+        }
+    }
+    SettingsCard(
+        "Sensitivity",
+        "${state.settings.wakeWord.sensitivity}% · Higher values detect more easily but may false-trigger."
+    ) {
+        Slider(
+            value = state.settings.wakeWord.sensitivity.toFloat(),
+            onValueChange = { setSensitivity(it.roundToInt()) },
+            valueRange = 0f..100f
+        )
+    }
+    SettingsCard(
+        "Listening controls",
+        "Testing releases this launcher’s microphone before opening the selected Android assistant."
+    ) {
+        Row(horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+            if (state.wakeWord.state == WakeWordState.PAUSED) {
+                Button(onClick = resume) { Text("Resume") }
+            } else {
+                OutlinedButton(
+                    onClick = pause,
+                    enabled = state.settings.wakeWord.enabled
+                ) { Text("Pause") }
+            }
+            Button(
+                onClick = test,
+                enabled = state.settings.wakeWord.enabled &&
+                    state.wakeWord.modelState == ModelInstallState.READY
+            ) {
+                Icon(Icons.Default.Mic, null)
+                Spacer(Modifier.width(7.dp))
+                Text("Test assistant")
+            }
+        }
+        OutlinedButton(
+            onClick = {
+                runCatching { context.startActivity(Intent(Settings.ACTION_VOICE_INPUT_SETTINGS)) }
+            }
+        ) {
+            Text("Open Android voice settings")
+        }
+    }
+    SettingsCard(
+        "Privacy",
+        "Audio frames are processed locally and are never saved or transmitted."
+    ) {
+        Text("Only the last detection time and service status are retained for diagnostics.")
+    }
+}
+
 @Composable
 private fun ApplicationsSettings(
     state: LauncherUiState,
@@ -929,10 +1081,24 @@ private fun AccessSettings(requestHomeRole: () -> Unit) = SettingsPage("System a
     PermissionStatus("Internet", true, "Used for weather and the built-in online photo collection.")
     PermissionStatus("Local photo folder", true, "Granted only to the folder you explicitly select.")
     PermissionStatus("Location", false, "Not requested. Weather uses coordinates entered in settings.")
-    PermissionStatus("Microphone", false, "Not requested. No wake-word model is bundled.")
+    PermissionStatus(
+        "Microphone",
+        ContextCompat.checkSelfPermission(
+            LocalContext.current,
+            Manifest.permission.RECORD_AUDIO
+        ) == PackageManager.PERMISSION_GRANTED,
+        "Requested only when on-device wake-word listening is enabled."
+    )
     PermissionStatus("Display over other apps", false, "Not requested. Ultra-dim only covers this launcher.")
     PermissionStatus("Usage access", false, "Not requested. Recent-app history is not collected.")
-    PermissionStatus("Notifications", false, "Not requested because no background voice service runs.")
+    PermissionStatus(
+        "Notifications",
+        Build.VERSION.SDK_INT < 33 || ContextCompat.checkSelfPermission(
+            LocalContext.current,
+            Manifest.permission.POST_NOTIFICATIONS
+        ) == PackageManager.PERMISSION_GRANTED,
+        "Used for the visible listening service and assistant fallback action."
+    )
     SettingsCard(
         "Audio output",
         "A normal launcher cannot force other apps to use a specific device."