refactor: buildSrc convention plugin + direct enum mapping for tile conversion

buildSrc convention plugin migration:
- Move codegen task registration (generateMessageIndex,
  generateLocalizedConfigs, verifyMahjongTileResources,
  generateCraftEngineBundle) and native build task registration
  (configureGbMahjongNative, buildGbMahjongNative,
  packageGbMahjongNative) into MahjongTaskRegistration.kt in
  buildSrc.
- build.gradle.kts shrinks from 359 to 192 lines; it now just
  applies plugins, declares dependencies, and delegates task
  registration to the buildSrc helper.
- Architecture budget for build.gradle.kts lowered 380 -> 210.

Direct enum mapping for riichi <-> model MahjongTile:
- GbRoundSupport.toRiichiTile/fromRiichiTile previously called
  valueOf(tile.name()) on every conversion, paying for a string
  round-trip through the enum cache.
- Replace with two unmodifiable EnumMap lookups built once at
  class init. Both enums share identical constant names, so the
  maps are complete.

Author: Arbousier1

build.gradle.kts

@@ -1,9 +1,5 @@
-import org.gradle.api.GradleException
 import org.gradle.api.tasks.testing.Test
-import top.ellan.mahjong.build.CraftEngineBundleGenerator
-import top.ellan.mahjong.build.MahjongCodegen
-import top.ellan.mahjong.build.NativeBuildSupport
-import java.io.File
+import top.ellan.mahjong.build.MahjongTaskRegistration
 
 plugins {
     java
@@ -19,12 +15,10 @@ group = "top.ellan"
 version = "1.3.0-SNAPSHOT"
 
 val minimumPaperDevBundleVersion = "1.20.1-R0.1-SNAPSHOT"
-val latestPaperDevBundleVersion = "26.2-rc-2.build.9-alpha"
-val supportedPaperApiVersion = "1.20"
 val paperDevBundleVersion = providers.gradleProperty("mahjongPaperDevBundle")
     .orElse(minimumPaperDevBundleVersion)
     .get()
-// Keep plugin descriptors pinned to the lowest supported Paper API so one jar can load on newer Paper versions.
+val supportedPaperApiVersion = "1.20"
 val paperApiVersion = supportedPaperApiVersion
 val javaTargetVersion = providers.gradleProperty("mahjongJavaTarget")
     .map(String::toInt)
@@ -41,7 +35,6 @@ val mysqlVersion = "9.7.0"
 val h2Version = "2.4.240"
 val hikariVersion = "7.1.0"
 val caffeineVersion = "3.2.0"
-// Keep explicit Adventure APIs on the Paper 1.20.1 line so the jar stays runtime-compatible with older servers.
 val adventureVersion = "4.14.0"
 val junitVersion = "6.1.0"
 val testcontainersVersion = "1.21.4"
@@ -55,146 +48,13 @@ repositories {
     maven("https://jitpack.io")
 }
 
-val generateMessageIndex = tasks.register("generateMessageIndex") {
-    val inputDir = layout.projectDirectory.dir("src/main/resources").asFile
-    val outputFile = generatedResourcesDir.map { it.file("i18n/_index.json") }.get().asFile
-    inputs.dir(inputDir)
-    outputs.file(outputFile)
-    doLast {
-        MahjongCodegen.writeMessageIndex(inputDir, outputFile, "zh-CN")
-    }
-}
-
-val generateLocalizedConfigs = tasks.register("generateLocalizedConfigs") {
-    val templateFile = layout.projectDirectory.file("src/main/config-template/config.template.yml").asFile
-    val translations = linkedMapOf(
-        "config.yml" to layout.projectDirectory.file("src/main/config-template/config_comments_en.properties").asFile,
-        "config_zh_CN.yml" to layout.projectDirectory.file("src/main/config-template/config_comments_zh_CN.properties").asFile,
-        "config_zh_TW.yml" to layout.projectDirectory.file("src/main/config-template/config_comments_zh_TW.properties").asFile
-    )
-    val outputDir = generatedResourcesDir.get().asFile
-
-    inputs.file(templateFile)
-    translations.values.forEach { inputs.file(it) }
-    outputs.files(translations.keys.map { outputDir.resolve(it) })
-
-    doLast {
-        outputDir.mkdirs()
-        val template = templateFile.readText(Charsets.UTF_8)
-        translations.forEach { (targetFileName, translationFile) ->
-            val rendered = MahjongCodegen.renderTemplateWithTokens(template, MahjongCodegen.loadUtf8Properties(translationFile))
-            outputDir.resolve(targetFileName).writeText(rendered, Charsets.UTF_8)
-        }
-    }
-}
-
-val verifyMahjongTileResources = tasks.register("verifyMahjongTileResources") {
-    val enumSource = layout.projectDirectory.file("src/main/java/top/ellan/mahjong/model/MahjongTile.java").asFile
-    val itemsDir = layout.projectDirectory.dir("resourcepack/assets/mahjongcraft/items/mahjong_tile").asFile
-    val modelsDir = layout.projectDirectory.dir("resourcepack/assets/mahjongcraft/models/item/mahjong_tile").asFile
-    val texturesDir = layout.projectDirectory.dir("resourcepack/assets/mahjongcraft/textures/item/mahjong_tile").asFile
-    val outputFile = generatedResourcesDir.map { it.file("resourcepack/mahjong_tile_index.json") }.get().asFile
-    inputs.file(enumSource)
-    inputs.dir(itemsDir)
-    inputs.dir(modelsDir)
-    inputs.dir(texturesDir)
-    outputs.file(outputFile)
-    doLast {
-        MahjongCodegen.writeMahjongTileResourceIndex(enumSource, itemsDir, modelsDir, texturesDir, outputFile)
-    }
-}
-
-val generateCraftEngineBundle = tasks.register("generateCraftEngineBundle") {
-    val enumSource = layout.projectDirectory.file("src/main/java/top/ellan/mahjong/model/MahjongTile.java").asFile
-    val resourcepackDir = layout.projectDirectory.dir("resourcepack").asFile
-    val attributionFile = layout.projectDirectory.file("resourcepack/ATTRIBUTION.md").asFile
-    val outputDir = generatedResourcesDir.get().asFile
-    inputs.file(enumSource)
-    inputs.dir(resourcepackDir)
-    inputs.file(attributionFile)
-    outputs.dir(outputDir.resolve("craftengine"))
-    doLast {
-        CraftEngineBundleGenerator.writeCraftEngineBundle(enumSource, resourcepackDir, attributionFile, outputDir, project.version.toString())
-    }
-}
-
-val gbNativeSourceDir = layout.projectDirectory.dir("native/gbmahjong")
-val gbNativeBuildDir = layout.buildDirectory.dir("native/gbmahjong")
-val gbNativeCmakeExecutable = NativeBuildSupport.findExecutable("cmake")
-val gbNativeGxxExecutable = NativeBuildSupport.findExecutable("g++")
-val gbNativeNinjaExecutable = NativeBuildSupport.findExecutable("ninja")
-val gbNativeToolchainAvailable = gbNativeCmakeExecutable != null && gbNativeGxxExecutable != null
-val gbNativeWindowsRuntimeDir = gbNativeGxxExecutable?.let { File(it).parentFile }
-val gbNativeCurrentOsName = System.getProperty("os.name", "")
-val gbNativeCurrentArch = System.getProperty("os.arch", "")
-val gbNativePlatformKey = NativeBuildSupport.nativePlatformKey(gbNativeCurrentOsName, gbNativeCurrentArch)
-val gbNativeLibraryFileName = NativeBuildSupport.nativeLibraryFileName(gbNativeCurrentOsName)
-
-val configureGbMahjongNative = tasks.register<Exec>("configureGbMahjongNative") {
-    group = "build"
-    description = "Configure the JNI GB Mahjong native project with CMake."
-    onlyIf { gbNativeToolchainAvailable }
-    val sourceDir = gbNativeSourceDir.asFile
-    val buildDir = gbNativeBuildDir.get().asFile
-    inputs.dir(sourceDir)
-    outputs.dir(buildDir)
-    doFirst {
-        buildDir.mkdirs()
-    }
-    val command = mutableListOf(
-        gbNativeCmakeExecutable ?: "cmake",
-        "-S", sourceDir.absolutePath,
-        "-B", buildDir.absolutePath
-    )
-    if (gbNativeNinjaExecutable != null) {
-        command += listOf("-G", "Ninja", "-DCMAKE_MAKE_PROGRAM=${gbNativeNinjaExecutable}")
-    }
-    if (gbNativeGxxExecutable != null) {
-        command += listOf("-DCMAKE_CXX_COMPILER=${gbNativeGxxExecutable}")
-    }
-    commandLine(command)
-}
-
-val buildGbMahjongNative = tasks.register<Exec>("buildGbMahjongNative") {
-    group = "build"
-    description = "Build the JNI GB Mahjong native project with CMake."
-    dependsOn(configureGbMahjongNative)
-    onlyIf { gbNativeToolchainAvailable }
-    val buildDir = gbNativeBuildDir.get().asFile
-    inputs.dir(gbNativeSourceDir)
-    outputs.dir(buildDir)
-    commandLine(
-        gbNativeCmakeExecutable ?: "cmake",
-        "--build", buildDir.absolutePath,
-        "--config", "Release"
-    )
-}
-
-val packageGbMahjongNative = tasks.register("packageGbMahjongNative") {
-    group = "build"
-    description = "Copy built GB Mahjong native runtime files into generated resources."
-    dependsOn(buildGbMahjongNative)
-    onlyIf { gbNativeToolchainAvailable }
-    val buildDir = gbNativeBuildDir.get().asFile
-    val outputDir = generatedNativeResourcesDir.get().asFile.resolve("native/$gbNativePlatformKey")
-    inputs.dir(buildDir)
-    outputs.dir(outputDir)
-    doLast {
-        outputDir.mkdirs()
-        val library = buildDir.resolve(gbNativeLibraryFileName)
-        if (!library.isFile) {
-            throw GradleException("Expected GB Mahjong native library at ${library.absolutePath}")
-        }
-        library.copyTo(outputDir.resolve(library.name), overwrite = true)
-
-        if (gbNativePlatformKey == "windows-x86_64") {
-            val winPthread = gbNativeWindowsRuntimeDir?.resolve("libwinpthread-1.dll")
-            if (winPthread?.isFile == true) {
-                winPthread.copyTo(outputDir.resolve(winPthread.name), overwrite = true)
-            }
-        }
-    }
-}
+// Codegen + native build tasks are registered via buildSrc convention helpers.
+val codegenTasks = MahjongTaskRegistration.registerCodegenTasks(
+    project, generatedResourcesDir, project.version.toString()
+)
+val nativeTasks = MahjongTaskRegistration.registerNativeTasks(
+    project, generatedNativeResourcesDir
+)
 
 dependencies {
     paperweight.paperDevBundle(paperDevBundleVersion)
@@ -217,9 +77,6 @@ dependencies {
     testImplementation("org.testcontainers:testcontainers:$testcontainersVersion")
     testImplementation("org.testcontainers:junit-jupiter:$testcontainersVersion")
     testImplementation("org.testcontainers:mariadb:$testcontainersVersion")
-    // Tests follow whichever Adventure version the active paperDevBundle ships with so that
-    // paper-api's compiled-against interfaces (e.g. ComponentDecoder added in Adventure 4.16) resolve
-    // at runtime. Production code is still constrained to the older surface via the compileOnly BOM above.
     testImplementation("net.kyori:adventure-api")
     testImplementation("net.kyori:adventure-text-minimessage")
     testImplementation("net.kyori:adventure-text-serializer-plain")
@@ -256,7 +113,7 @@ tasks {
     }
 
     processResources {
-        dependsOn(generateMessageIndex, generateLocalizedConfigs, verifyMahjongTileResources, generateCraftEngineBundle, packageGbMahjongNative)
+        dependsOn(codegenTasks + nativeTasks)
         filteringCharset = Charsets.UTF_8.name()
         inputs.property("pluginVersion", project.version.toString())
         inputs.property("paperApiVersion", paperApiVersion)
@@ -322,16 +179,14 @@ tasks {
 
     check {
         dependsOn(jacocoTestReport)
-        dependsOn(verifyMahjongTileResources)
-        dependsOn(generateCraftEngineBundle)
+        dependsOn("verifyMahjongTileResources")
+        dependsOn("generateCraftEngineBundle")
         dependsOn("spotlessCheck")
         dependsOn("detekt")
     }
 }
 
 spotless {
-    // Ratchet: only enforce formatting on files that changed relative to the
-    // dev branch, so existing code is not reformatted in one giant commit.
     ratchetFrom("origin/dev")
     kotlin {
         target("src/main/kotlin/**/*.kt", "src/test/kotlin/**/*.kt", "buildSrc/**/*.kt")
@@ -343,17 +198,13 @@ spotless {
     }
     java {
         target("src/main/java/**/*.java", "src/test/java/**/*.java")
-        // Remove trailing whitespace and ensure files end with a newline.
         trimTrailingWhitespace()
         endWithNewline()
     }
 }
 
 detekt {
-    // Permissive baseline: existing code has many style issues. New code is
-    // enforced via spotless; detekt focuses on code-smell rules going forward.
     buildUponDefaultConfig = true
     config.setFrom(files("$rootDir/config/detekt.yml"))
-    // Don't fail the build on existing violations; only fail on new severe issues.
     ignoreFailures = true
 }