Run the linter the app build already had, and fix what it found

`./gradlew :androidApp:lintDebug` had apparently never been run. It
reported 11 errors, 8 warnings and 3 hints, and one of the errors was a
crash: UsageScreen formats its reset countdown with java.time --
OffsetDateTime and Duration, both API 26 -- while minSdk is 24 and core
library desugaring was off. On 24 and 25 that is a NoClassDefFoundError,
and the `catch (_: Exception)` around the code does not stop an Error, so
the usage screen would have died rather than degraded.

Core library desugaring is now on, with desugar_jdk_libs 2.1.5. Verified
by looking in the built APK rather than trusting the flag: it now carries
Lj$/time/Duration and Lj$/time/OffsetDateTime, the backported classes the
call sites are rewritten against.

The rest: the two KTX suggestions taken (SharedPreferences.edit's block
form, which cannot forget its apply(), and String.toUri), the three
autoboxing hints taken (mutableIntStateOf/mutableLongStateOf), and
androidx.core:core-ktx declared at 1.19.0 rather than inherited through
activity-compose, since this code now calls its extensions directly.

Two are suppressed with their reasons, both scoped to the one element.
DiscouragedApi on the scanner's screenOrientation, which is not a pin but
the removal of the library's landscape lock. MissingApplicationIcon,
because there is no icon yet and that is a decision to make later, not an
oversight -- an app with no icon is obvious to anyone who opens a
launcher, so the warning tells nobody here anything.

0 errors now. The 4 warnings left are one thing: Compose Multiplatform
1.12.0 is out and this is on 1.11.1. That is an upgrade to decide on, not
a defect, so it is left for its own change.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017xn8nHw1tw1R6PtiY1eEtw

app/androidApp/build.gradle.kts

@@ -106,6 +106,11 @@ android {
     compileOptions {
         sourceCompatibility = JavaVersion.VERSION_21
         targetCompatibility = JavaVersion.VERSION_21
+        // minSdk is 24 and UsageScreen formats its countdown with
+        // java.time, which the platform only has from 26. Without this it
+        // is a NoClassDefFoundError on 24 and 25 -- an Error, so the
+        // catch around that code does not stop it.
+        isCoreLibraryDesugaringEnabled = true
     }
 }
 
@@ -121,10 +126,15 @@ androidComponents {
 }
 
 dependencies {
+    // Not a library this code calls: it is what `isCoreLibraryDesugaring
+    // Enabled` above rewrites java.time against, so API 24 and 25 have it.
+    coreLibraryDesugaring(libs.desugar.jdk.libs)
+
     implementation(libs.compose.runtime)
     implementation(libs.compose.foundation)
     implementation(libs.compose.material3)
     implementation(libs.compose.ui)
     implementation(libs.androidx.activity.compose)
+    implementation(libs.androidx.core.ktx)
     implementation(libs.zxing.embedded)
 }

app/androidApp/src/main/AndroidManifest.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools">
     <uses-permission android:name="android.permission.INTERNET" />
     <!-- Android 17 (API 37) made Local Network Protection mandatory: an app
          targeting 37+ needs this runtime permission to reach *any* local
@@ -9,10 +10,17 @@
          dev-updater's manifest for the full story. -->
     <uses-permission android:name="android.permission.ACCESS_LOCAL_NETWORK" />
 
+    <!-- tools:ignore MissingApplicationIcon: there is no icon yet, and
+         that is a decision rather than an oversight. An app with no icon
+         of its own is obvious to anyone who opens a launcher, so the
+         warning tells nobody here anything they cannot already see, and
+         the fix is a judgement about how this app should look. Drop this
+         suppression when a real icon lands. -->
     <application
         android:label="AI Sessions"
         android:allowBackup="true"
-        android:theme="@android:style/Theme.Material.Light.NoActionBar">
+        android:theme="@android:style/Theme.Material.Light.NoActionBar"
+        tools:ignore="MissingApplicationIcon">
         <!-- adjustResize (not the system's default pan): the layout handles
              the keyboard itself via imePadding(), so the window must resize
              rather than slide the top bar off screen. -->
@@ -46,12 +54,21 @@
              code being scanned is usually on a monitor in front of someone
              holding the phone upright. zxing_CaptureTheme is the library's
              own fullscreen theme, which is all the activity needs. -->
+        <!-- tools:ignore DiscouragedApi: lint flags every fixed
+             screenOrientation, because Android 16 ignores most of them.
+             This one is not a pin but its removal. fullSensor is what
+             drops the library's landscape lock, so the activity follows
+             the phone rather than asking anyone to turn it, and where the
+             platform ignores the attribute the behaviour is the one this
+             asked for anyway. Scoped to this activity, so a genuine pin
+             elsewhere would still be reported. -->
         <activity
             android:name=".EnrollmentScanActivity"
             android:clearTaskOnLaunch="true"
             android:screenOrientation="fullSensor"
             android:stateNotNeeded="true"
             android:theme="@style/zxing_CaptureTheme"
-            android:windowSoftInputMode="stateAlwaysHidden" />
+            android:windowSoftInputMode="stateAlwaysHidden"
+            tools:ignore="DiscouragedApi" />
     </application>
 </manifest>

app/androidApp/src/main/kotlin/com/example/aiapp/AppRoot.kt

@@ -3,6 +3,7 @@ package com.example.aiapp
 import androidx.activity.compose.BackHandler
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableIntStateOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
@@ -32,7 +33,7 @@ fun AppRoot(settingsVersion: Int) {
     var screen by remember { mutableStateOf<Screen>(Screen.SessionList) }
     // Bumped whenever another screen changes something the list shows, so
     // returning to it refetches instead of showing a stale list.
-    var reloadToken by remember { mutableStateOf(0) }
+    var reloadToken by remember { mutableIntStateOf(0) }
 
     val current = settings
     if (current == null) {

app/androidApp/src/main/kotlin/com/example/aiapp/MainActivity.kt

@@ -16,6 +16,7 @@ import androidx.compose.foundation.layout.statusBarsPadding
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableIntStateOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
@@ -24,7 +25,7 @@ import androidx.core.view.WindowCompat
 class MainActivity : ComponentActivity() {
     // Bumped whenever enrollment lands via an aiapp:// intent so the
     // composition below re-reads the stored settings.
-    private var settingsVersion by mutableStateOf(0)
+    private var settingsVersion by mutableIntStateOf(0)
 
     // Registered up front since permission launchers must be registered
     // before the activity reaches STARTED.

app/androidApp/src/main/kotlin/com/example/aiapp/ServerConfig.kt

@@ -2,6 +2,7 @@ package com.example.aiapp
 
 import android.content.Context
 import android.net.Uri
+import androidx.core.content.edit
 import android.security.keystore.KeyGenParameterSpec
 import android.security.keystore.KeyProperties
 import android.util.Base64
@@ -37,12 +38,11 @@ fun loadServerSettings(context: Context): ServerSettings? {
 }
 
 fun saveServerSettings(context: Context, settings: ServerSettings) {
-    context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE)
-        .edit()
-        .putString(KEY_HOST, settings.host)
-        .putInt(KEY_PORT, settings.port)
-        .putString(KEY_TOKEN, seal(settings.token))
-        .apply()
+    context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE).edit {
+        putString(KEY_HOST, settings.host)
+        putInt(KEY_PORT, settings.port)
+        putString(KEY_TOKEN, seal(settings.token))
+    }
 }
 
 /**

app/androidApp/src/main/kotlin/com/example/aiapp/SessionScreen.kt

@@ -33,6 +33,7 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableLongStateOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
@@ -124,7 +125,7 @@ fun SessionScreen(settings: ServerSettings, summary: SessionSummary, onBack: ()
     val scope = rememberCoroutineScope()
     var items by remember { mutableStateOf(listOf<TranscriptItem>()) }
     var status by remember { mutableStateOf(summary.status) }
-    var totalTokens by remember { mutableStateOf(0L) }
+    var totalTokens by remember { mutableLongStateOf(0L) }
     var streamError by remember { mutableStateOf<String?>(null) }
     var actionError by remember { mutableStateOf<String?>(null) }
     var input by remember { mutableStateOf("") }

app/androidApp/src/main/kotlin/com/example/aiapp/SettingsScreen.kt

@@ -25,6 +25,7 @@ import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.unit.dp
+import androidx.core.net.toUri
 import androidx.activity.compose.rememberLauncherForActivityResult
 import androidx.activity.result.contract.ActivityResultContracts
 import com.google.zxing.client.android.Intents
@@ -56,7 +57,7 @@ fun SettingsScreen(
         // Null contents means the user backed out of the scanner -- not an
         // error, so nothing to report.
         val contents = result.contents ?: return@rememberLauncherForActivityResult
-        val settings = parseEnrollmentUri(Uri.parse(contents))
+        val settings = parseEnrollmentUri(contents.toUri())
         if (settings == null) {
             error = "Not a valid enrollment code"
         } else {

app/gradle/libs.versions.toml

@@ -8,15 +8,25 @@ compose-multiplatform = "1.11.1"
 # material3 ships on its own release train, separate from the CMP version.
 compose-material3 = "1.9.0"
 androidx-activityCompose = "1.13.0"
+# Declared rather than inherited because this
+# code now calls its extensions directly (SharedPreferences.edit, String
+# .toUri), and a transitive it merely inherited could change under it.
+androidx-core-ktx = "1.19.0"
 zxing-embedded = "4.3.0"
+# Backports java.time (and more) to API 24, which UsageScreen needs: its
+# reset countdown is OffsetDateTime/Duration, both API 26. Checked
+# 2026-08-28 against Google Maven.
+desugar-jdk-libs = "2.1.5"
 
 [libraries]
 androidx-activity-compose = { module = "androidx.activity:activity-compose", version.ref = "androidx-activityCompose" }
+androidx-core-ktx = { module = "androidx.core:core-ktx", version.ref = "androidx-core-ktx" }
 # In-app QR scanner: a ready-made scanning Activity (camera preview, runtime
 # permission prompt, flashlight toggle) reached through the AndroidX Activity
 # Result API (ScanContract, added in 4.3.0). Fully offline -- no Play
 # Services / ML Kit model download involved.
 zxing-embedded = { module = "com.journeyapps:zxing-android-embedded", version.ref = "zxing-embedded" }
+desugar-jdk-libs = { module = "com.android.tools:desugar_jdk_libs", version.ref = "desugar-jdk-libs" }
 # Declared directly rather than through the plugin's `compose.*` accessors,
 # which are deprecated as of CMP 1.11.
 compose-runtime = { module = "org.jetbrains.compose.runtime:runtime", version.ref = "compose-multiplatform" }