M0: scaffold bnstoolkit mod (NeoForge 1.21.1)

Empty mod that loads cleanly on client + dedicated server. Sets up the
package layout and milestone TODOs for the BNS in-game UI work.

- uk.sijbers.bnstoolkit.{BnsToolkit, BnsToolkitClient} mod entries
- 5 placeholder screens extending a shared BaseBnsScreen
  (TierUpgrade, BountyBoard, QuestLog, PlotPurchase, ShopBrowser)
- 3 key bindings (T/B/P) registered, handlers TODO M1+
- SpurHud overlay placeholder for M4
- Network: payload registrar + one smoke-test C2S/S2C pair
  (RequestTierState / TierStateUpdate)
- en_us.json for screen + keybind labels
- neoforge.mods.toml pinned to neo_version 21.1.228 (live server match)

Build verified: ./gradlew build -> bnstoolkit-0.1.0.jar (15.6 KB).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

build.gradle

@@ -0,0 +1,134 @@
+plugins {
+    id 'java-library'
+    id 'maven-publish'
+    id 'net.neoforged.moddev' version '2.0.141'
+    id 'idea'
+}
+
+tasks.named('wrapper', Wrapper).configure {
+    distributionType = Wrapper.DistributionType.BIN
+}
+
+version = mod_version
+group = mod_group_id
+
+sourceSets.main.resources {
+    srcDir('src/generated/resources')
+    exclude("**/*.bbmodel")
+    exclude("src/generated/**/.cache")
+}
+
+repositories {
+    // FTB Library / FTB Chunks / FTB Quests live here. Used compileOnly
+    // when we wire screens to the FTB UI framework (M1+).
+    maven {
+        name = 'FTB'
+        url = 'https://maven.ftb.dev/releases'
+        content { includeGroup 'dev.ftb.mods' }
+    }
+    // Numismatics + Create dependencies live on Modrinth's maven mirror.
+    maven {
+        name = 'ModrinthMaven'
+        url = 'https://api.modrinth.com/maven'
+    }
+}
+
+base {
+    archivesName = mod_id
+}
+
+java.toolchain.languageVersion = JavaLanguageVersion.of(21)
+
+neoForge {
+    version = project.neo_version
+
+    parchment {
+        mappingsVersion = project.parchment_mappings_version
+        minecraftVersion = project.parchment_minecraft_version
+    }
+
+    runs {
+        client {
+            client()
+            systemProperty 'neoforge.enabledGameTestNamespaces', project.mod_id
+        }
+
+        server {
+            server()
+            programArgument '--nogui'
+            systemProperty 'neoforge.enabledGameTestNamespaces', project.mod_id
+        }
+
+        data {
+            data()
+            programArguments.addAll '--mod', project.mod_id, '--all', '--output', file('src/generated/resources/').getAbsolutePath(), '--existing', file('src/main/resources/').getAbsolutePath()
+        }
+
+        configureEach {
+            systemProperty 'forge.logging.markers', 'REGISTRIES'
+            logLevel = org.slf4j.event.Level.DEBUG
+        }
+    }
+
+    mods {
+        "${mod_id}" {
+            sourceSet(sourceSets.main)
+        }
+    }
+}
+
+configurations {
+    runtimeClasspath.extendsFrom localRuntime
+}
+
+dependencies {
+    // TODO(matt M1): wire FTB Library compileOnly dep when first FTB-UI screen lands.
+    // Candidate coord (verify version pinning against pack):
+    //   compileOnly "dev.ftb.mods:ftb-library-neoforge:2101.1.31"
+    //
+    // TODO(matt M2): Numismatics compileOnly dep for the shop block integration.
+    // Modrinth maven path: maven.modrinth/numismatics/<version>
+}
+
+var generateModMetadata = tasks.register("generateModMetadata", ProcessResources) {
+    var replaceProperties = [
+            minecraft_version      : minecraft_version,
+            minecraft_version_range: minecraft_version_range,
+            neo_version            : neo_version,
+            loader_version_range   : loader_version_range,
+            mod_id                 : mod_id,
+            mod_name               : mod_name,
+            mod_license            : mod_license,
+            mod_version            : mod_version,
+    ]
+    inputs.properties replaceProperties
+    expand replaceProperties
+    from "src/main/templates"
+    into "build/generated/sources/modMetadata"
+}
+sourceSets.main.resources.srcDir generateModMetadata
+neoForge.ideSyncTask generateModMetadata
+
+publishing {
+    publications {
+        register('mavenJava', MavenPublication) {
+            from components.java
+        }
+    }
+    repositories {
+        maven {
+            url "file://${project.projectDir}/repo"
+        }
+    }
+}
+
+tasks.withType(JavaCompile).configureEach {
+    options.encoding = 'UTF-8'
+}
+
+idea {
+    module {
+        downloadSources = true
+        downloadJavadoc = true
+    }
+}