Complete Stage 0: Project scaffold

- Fix build.gradle.kts: Java 21, Paper 1.20.6, ProtocolLib 5.3.0
- Add permissions to paper-plugin.yml
- Add ConfigManager with safe yaml loading (no overwrite)
- Add LocationsConfig for all game object coordinates
- Add GameConfig with all balance values
- Update mdbd.java with onEnable/onDisable + ConfigManager
- Mark Stage 0 complete in PLAN.md

build.gradle.kts

@@ -6,22 +6,21 @@ plugins {
 repositories {
     mavenCentral()
     maven("https://repo.papermc.io/repository/maven-public/")
+    maven("https://repo.dmulloy2.net/repository/public/")
 }
 
 dependencies {
-    compileOnly("io.papermc.paper:paper-api:26.1.2.build.+")
+    compileOnly("io.papermc.paper:paper-api:1.20.6-R0.1-SNAPSHOT")
+    compileOnly("com.comphenix.protocol:ProtocolLib:5.3.0")
 }
 
 java {
-    toolchain.languageVersion = JavaLanguageVersion.of(25)
+    toolchain.languageVersion = JavaLanguageVersion.of(21)
 }
 
 tasks {
     runServer {
-        // Configure the Minecraft version for our task.
-        // This is the only required configuration besides applying the plugin.
-        // Your plugin's jar (or shadowJar if present) will be used automatically.
-        minecraftVersion("26.1.2")
+        minecraftVersion("1.20.6")
         jvmArgs("-Xms2G", "-Xmx2G")
     }