docs: update README with features, build instructions, and desktop JVM toolchain fix

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

README.MD

@@ -1,5 +1,19 @@
 # ShadowrunCharSheet
 
+A Kotlin Multiplatform character sheet application for Shadowrun 5th Edition, built with Compose Multiplatform. Supports Android, Desktop (JVM), Web (JS + WASM), and iOS.
+
+## Features
+
+- **Character Management** — Create, edit, import/export characters as JSON
+- **Attributes & Talents** — Full Shadowrun 5e attribute system with 60+ predefined talents
+- **Dice Rolling** — Built-in dice roller with success counting and roll history
+- **Damage Monitor** — Stun, physical, and overflow damage tracking with wound modifiers
+- **Responsive UI** — Adaptive layout with window size classes for all screen sizes
+- **Theming** — Material 3 with dark/light mode and theme color selection
+- **Cross-Platform** — Single shared codebase across Android, Desktop, Web, and iOS
+
+## Platforms
+
 ### Android
 To run the application on android device/emulator:
  - open project in Android Studio and run imported android run configuration
@@ -12,6 +26,9 @@ To build the application bundle:
 Run the desktop application: `./gradlew :desktopApp:run`
 Run the desktop **hot reload** application: `./gradlew :desktopApp:hotRun --auto`
 
+Build a standalone uber JAR: `./gradlew :desktopApp:packageUberJarForCurrentOS`
+ - find `.jar` file in `desktopApp/build/compose/jars/`
+
 ### iOS
 To run the application on iPhone device/simulator:
  - Open `iosApp/iosApp.xcproject` in Xcode and run standard configuration
@@ -19,11 +36,30 @@ To run the application on iPhone device/simulator:
 
 ### Web Distribution
 Build web distribution: `./gradlew :webApp:composeCompatibilityBrowserDistribution`
-Deploy a dir `webApp/build/dist/composeWebCompatibility/productionExecutable` to a web server  
+Deploy the dir `webApp/build/dist/composeWebCompatibility/productionExecutable` to a web server
 
-### JS Browser
+### JS Browser (Development)
 Run the browser application: `./gradlew :webApp:jsBrowserDevelopmentRun`
 
-### Wasm Browser
+### Wasm Browser (Development)
 Run the browser application: `./gradlew :webApp:wasmJsBrowserDevelopmentRun`
 
+## Testing
+
+Run all tests:
+```
+./gradlew :sharedUI:allTests
+```
+
+Run a single test class:
+```
+./gradlew :sharedUI:jvmTest --tests "org.shahondin1624.ComposeTest"
+```
+
+## Architecture
+
+Kotlin Multiplatform project with all shared logic and UI in the `sharedUI` module. Platform modules (`androidApp`, `desktopApp`, `webApp`, `iosApp`) are thin entry points.
+
+Key dependencies: Compose Multiplatform, kotlinx.serialization, MaterialKolor, KStore, Ktor, Coil.
+
+See `CLAUDE.md` for detailed architecture documentation.

desktopApp/build.gradle.kts

@@ -8,6 +8,10 @@ plugins {
     alias(libs.plugins.compose.hot.reload)
 }
 
+kotlin {
+    jvmToolchain(24)
+}
+
 dependencies {
     implementation(project(":sharedUI"))
     implementation(compose.ui)