add CLAUDE.md and enable resource shrinking for release builds

Author: modelorona

CLAUDE.md

@@ -0,0 +1,45 @@
+# TapLock
+
+Android screen-lock utility using accessibility services and widgets. Single-module Kotlin/Compose app.
+
+## Commands
+
+```bash
+./gradlew assembleDebug          # Build debug APK
+./gradlew testDebugUnitTest      # Unit tests (DoubleTapDetector)
+./gradlew connectedAndroidTest   # Instrumented UI tests (requires device/emulator)
+./gradlew lintDebug              # Lint checks
+```
+
+## Architecture
+
+Single `:app` module. All source in `app/src/main/java/com/ah/taplock/`:
+
+- **MainActivity.kt** — Compose settings UI, onboarding flow, permission management
+- **TapLockAccessibilityService.kt** — Core service: overlay management, double-tap detection on status bar and lock screen
+- **TapLockWidgetProvider.kt** — RemoteViews-based 1x1 widget
+- **FloatingButtonService.kt** — Draggable overlay button (foreground service)
+- **TapLockTileService.kt** — Quick Settings tile
+- **DoubleTapDetector.kt** — Time-window tap detection with injectable clock
+- **VibrationHelper.kt** — API-level-aware vibration (Android 13+ vs older)
+- **Utils.kt** — Accessibility state check utility
+
+## Build Config
+
+- Min SDK 31 (Android 12), Target/Compile SDK 36
+- Java 21, Kotlin 2.3.20, AGP 9.2.0
+- Dependencies managed via `gradle/libs.versions.toml`
+- R8 minification enabled for release builds
+
+## Code Style
+
+Kotlin official style (`kotlin.code.style=official`). No detekt/ktlint — use `./gradlew lintDebug`.
+
+## Gotchas
+
+- `TapLockAccessibilityService.instance` is intentionally static (`@Suppress("StaticFieldLeak")`). Cleared in `onUnbind()`/`onDestroy()`. Don't add another static reference.
+- Overlay touch handling: must call `performClick()` after ACTION_UP. Overlay height changes reset the double-tap detector to prevent false positives.
+- Lock screen tap zone detection uses depth-first traversal to find clickable nodes — touches near interactive elements are forwarded, not counted.
+- Widget uses RemoteViews (no Compose). Custom icon requires manual cache invalidation via ACTION_APPWIDGET_UPDATE broadcast.
+- VibrationHelper branches on Build.VERSION for Android 13+. Both paths must be maintained.
+- SharedPreferences are synchronous throughout — changes immediately trigger recomposition via preference listener.

app/build.gradle.kts

@@ -20,6 +20,8 @@ android {
     buildTypes {
         release {
             isMinifyEnabled = true
+            isShrinkResources = true
+            isCrunchPngs = true
             proguardFiles(
                 getDefaultProguardFile("proguard-android-optimize.txt"),
                 "proguard-rules.pro"