Fix chat composer overlapping nav bar, remove focus mode toggle

[yuga-hashimoto]

Summary

• The chat screen's bottom chip row (agent mode / auto-accept / context usage, in ChatComposer inside ChatHomeScreen.kt) only had imePadding(), no navigation-bar inset handling. On devices/OS states that draw content edge-to-edge, this let the row render partially behind the system navigation bar (matches the reported screenshots: the "build" mode chip and neighboring controls sitting right against/under the 3-button nav bar). Added navigationBarsPadding() alongside the existing imePadding().
• Removed the "focus mode" fullscreen-toggle FAB (FocusModeOverlay, top-right corner button). Tapping it hid the chat title, drawer (hamburger) button, and new-chat ("+") button with no other way to bring them back — confusing, unrequested behavior. Deleted FocusModeOverlay.kt and its wiring (focusMode state, the AnimatedVisibility wrapper around the top app bar, and the FAB call) since nothing else referenced it.

Test plan

• ./gradlew :app:compileDebugKotlin (could not run in this sandbox — no Android SDK available; changes only add a standard, stable androidx.compose.foundation.layout modifier and remove now-dead code/state)
• Manually verify on a device with 3-button navigation that the mode/context chip row no longer overlaps the nav bar
• Manually verify the top app bar (title, hamburger, +) no longer has a fullscreen-toggle button and is always visible

[github-actions]

API 34 emulator screenshot failure

Diagnostic logs were uploaded as the emulator-ui-diagnostics-30145774732 workflow artifact.

> Task :app:stripDebugDebugSymbols
Unable to strip the following libraries, packaging them as they are: libandroid-shmem.so, libandroidx.graphics.path.so, libopencode_android_proot.so, libopencode_android_proot_loader.so, libopencode_android_proot_loader32.so, libtalloc.so, libtensorflowlite_jni.so.

> Task :app:processDebugAndroidTestManifest
> Task :app:generateDebugAndroidTestBuildConfig
> Task :app:generateDebugAndroidTestResValues
> Task :app:checkDebugAndroidTestAarMetadata
> Task :app:mapDebugAndroidTestSourceSetPaths
> Task :app:generateDebugAndroidTestResources
> Task :app:javaPreCompileDebugAndroidTest
> Task :app:mergeDebugAndroidTestShaders
> Task :app:compileDebugAndroidTestShaders NO-SOURCE
> Task :app:generateDebugAndroidTestAssets UP-TO-DATE
> Task :app:mergeDebugAndroidTestResources
> Task :app:mergeDebugAndroidTestAssets
> Task :app:compressDebugAndroidTestAssets
> Task :app:desugarDebugAndroidTestFileDependencies
> Task :app:processDebugAndroidTestResources
> Task :app:checkDebugAndroidTestDuplicateClasses
> Task :app:mergeDebugAndroidTestJniLibFolders
> Task :app:kspDebugKotlin
> Task :app:mergeExtDexDebugAndroidTest
> Task :app:mergeLibDexDebugAndroidTest
> Task :app:mergeDebugAndroidTestNativeLibs NO-SOURCE
> Task :app:stripDebugAndroidTestDebugSymbols NO-SOURCE
> Task :app:validateSigningDebugAndroidTest
> Task :app:writeDebugAndroidTestSigningConfigVersions
> Task :app:mergeExtDexDebug
> Task :app:compileDebugKotlin
w: file:///home/runner/work/opencode-android/opencode-android/app/src/main/java/com/opencode/android/feature/chat/LiveTranscriptOverlay.kt:107:44 'val Icons.Filled.Send: ImageVector' is deprecated. Use the AutoMirrored version at Icons.AutoMirrored.Filled.Send.
w: file:///home/runner/work/opencode-android/opencode-android/app/src/main/java/com/opencode/android/feature/chat/OpenCodeChatScreen.kt:678:5 'fun ClickableText(text: AnnotatedString, modifier: Modifier = ..., style: TextStyle = ..., softWrap: Boolean = ..., overflow: TextOverflow = ..., maxLines: Int = ..., onTextLayout: (TextLayoutResult) -> Unit = ..., onClick: (Int) -> Unit): Unit' is deprecated. Use Text or BasicText and pass an AnnotatedString that contains a LinkAnnotation.
w: file:///home/runner/work/opencode-android/opencode-android/app/src/main/java/com/opencode/android/feature/search/CommandPalette.kt:103:46 'val Icons.Filled.Chat: ImageVector' is deprecated. Use the AutoMirrored version at Icons.AutoMirrored.Filled.Chat.
w: file:///home/runner/work/opencode-android/opencode-android/app/src/main/java/com/opencode/android/feature/settings/SettingsScreen.kt:132:34 'fun Modifier.menuAnchor(): Modifier' is deprecated. Use overload that takes MenuAnchorType and enabled parameters.
w: file:///home/runner/work/opencode-android/opencode-android/app/src/main/java/com/opencode/android/feature/settings/SettingsScreenV2.kt:191:42 'val Icons.Filled.Chat: ImageVector' is deprecated. Use the AutoMirrored version at Icons.AutoMirrored.Filled.Chat.
w: file:///home/runner/work/opencode-android/opencode-android/app/src/main/java/com/opencode/android/feature/settings/SettingsScreenV2.kt:207:42 'val Icons.Filled.Chat: ImageVector' is deprecated. Use the AutoMirrored version at Icons.AutoMirrored.Filled.Chat.
w: file:///home/runner/work/opencode-android/opencode-android/app/src/main/java/com/opencode/android/feature/settings/SettingsScreenV2.kt:214:42 'val Icons.Filled.Chat: ImageVector' is deprecated. Use the AutoMirrored version at Icons.AutoMirrored.Filled.Chat.
w: file:///home/runner/work/opencode-android/opencode-android/app/src/main/java/com/opencode/android/ui/components/FileTypeIcon.kt:82:52 'val Icons.Filled.InsertDriveFile: ImageVector' is deprecated. Use the AutoMirrored version at Icons.AutoMirrored.Filled.InsertDriveFile.
w: file:///home/runner/work/opencode-android/opencode-android/app/src/main/java/com/opencode/android/ui/theme/Theme.kt:145:20 'var statusBarColor: Int' is deprecated. Deprecated in Java.
w: file:///home/runner/work/opencode-android/opencode-android/app/src/main/java/com/opencode/android/ui/theme/Theme.kt:146:20 'var navigationBarColor: Int' is deprecated. Deprecated in Java.

> Task :app:compileDebugJavaWithJavac
> Task :app:dexBuilderDebug
> Task :app:mergeDebugGlobalSynthetics
> Task :app:processDebugJavaRes
> Task :app:bundleDebugClassesToCompileJar
> Task :app:mergeProjectDexDebug
> Task :app:mergeDebugJavaResource
> Task :app:kspDebugAndroidTestKotlin
> Task :app:packageDebug
> Task :app:createDebugApkListingFileRedirect
> Task :app:assembleDebug

> Task :app:compileDebugAndroidTestKotlin FAILED
e: file:///home/runner/work/opencode-android/opencode-android/app/src/androidTest/java/com/opencode/android/ui/UiScreenshotInstrumentedTest.kt:139:29 No value passed for parameter 'workspaces'.
e: file:///home/runner/work/opencode-android/opencode-android/app/src/androidTest/java/com/opencode/android/ui/UiScreenshotInstrumentedTest.kt:139:29 No value passed for parameter 'selectedWorkspacePath'.
e: file:///home/runner/work/opencode-android/opencode-android/app/src/androidTest/java/com/opencode/android/ui/UiScreenshotInstrumentedTest.kt:139:29 No value passed for parameter 'onSelectProject'.
e: file:///home/runner/work/opencode-android/opencode-android/app/src/androidTest/java/com/opencode/android/ui/UiScreenshotInstrumentedTest.kt:276:17 No value passed for parameter 'wakeWordEnabled'.
e: file:///home/runner/work/opencode-android/opencode-android/app/src/androidTest/java/com/opencode/android/ui/UiScreenshotInstrumentedTest.kt:276:17 No value passed for parameter 'onWakeWordChange'.
gradle/actions: Writing build results to /home/runner/work/_temp/.gradle-actions/build-results/emulator-1784957340724.json

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:compileDebugAndroidTestKotlin'.
> A failure occurred while executing org.jetbrains.kotlin.compilerRunner.GradleCompilerRunnerWithWorkers$GradleKotlinCompilerWorkAction
   > Compilation error. See log for more details

* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.
> Get more help at https://help.gradle.org.

BUILD FAILED in 14m 12s
63 actionable tasks: 63 executed
OK: killing emulator, bye bye

OK