Switch to Groovy DSL; add runServer task

Migrate the project from Gradle Kotlin DSL to Groovy DSL: update README to reference build.gradle/settings.gradle and change code blocks to Groovy. Remove build.gradle.kts. Add runServerJar and runServer tasks in build.gradle that depend on shadowJar and launch the Hytale server (uses hytaleHome paths, assets, and optional user mods). Bump plugin manifest version to 0.0.3 and set a concrete ServerVersion string. Fixed some issues.

README.md

@@ -6,7 +6,7 @@ A minimal, ready-to-use template for creating Hytale plugins with modern build t
 
 ## Features
 
-✅ **Modern Build System** - Gradle with Kotlin DSL  
+✅ **Modern Build System** - Gradle with Groovy DSL  
 ✅ **Automated Testing** - Custom Gradle plugin for one-command server testing  
 ✅ **Java 25** - Latest Java features  
 ✅ **ShadowJar** - Automatic dependency bundling  
@@ -51,9 +51,9 @@ Your plugin JAR will be in: `build/libs/TemplatePlugin-1.0.0.jar`
 
 When ready to customize, edit these files:
 
-**`settings.gradle.kts`:**
+**`settings.gradle`:**
 
-```kotlin
+```groovy
 rootProject.name = "your-plugin-name"
 ```
 
@@ -139,9 +139,9 @@ TemplatePlugin/
 │   └── resources/
 │       └── manifest.json            # Plugin metadata
 ├── .gitignore                       # Git ignore rules
-├── build.gradle.kts                 # Build configuration
+├── build.gradle                     # Build configuration
 ├── gradle.properties                # Project properties
-├── settings.gradle.kts              # Project settings
+├── settings.gradle                  # Project settings
 ├── LICENSE                          # MIT License
 └── README.md                        # This file
 ```
@@ -200,9 +200,9 @@ rm -rf run/
 
 ### Adding Dependencies
 
-Edit `build.gradle.kts`:
+Edit `build.gradle`:
 
-```kotlin
+```groovy
 dependencies {
     // Hytale API (provided by server)
     compileOnly(files("./HytaleServer.jar"))
@@ -221,9 +221,9 @@ dependencies {
 
 **Usage:**
 
-Edit `build.gradle.kts`:
+Edit `build.gradle`:
 
-```kotlin
+```groovy
 runHytale {
     jarUrl = "url to hytale server jar"
 }
@@ -322,7 +322,7 @@ GitHub Actions will automatically build and create a release with your plugin JA
 
 ### Server Won't Start
 
-1. Check that `jarUrl` in `build.gradle.kts` is correct
+1. Check that `jarUrl` in `build.gradle` is correct
 2. Verify Java 25 is installed: `java -version`
 3. Check logs in `run/logs/`