Built every mod target

- verify<Loader><version> builds, tests and verifies each Fabric, Forge and NeoForge jar for every mod target
- build<Loader><version> exports each verified jar to PluginOuts, removing stale jars of the same loader and version
- buildAllToOut exports the Bukkit jar and all mod target jars; checkAll runs every project check plus the full mod matrix
- Targets list their unit test loaders; Forge 1.21.1 compiles its tests only because Forge 52 cannot bootstrap Minecraft outside FML
- Removed the single-target fabricJar, forgeJar, neoforgeJar, moddedTest and artifact verification tasks

gradle/mod-targets.json

@@ -8,6 +8,10 @@
     "neoForge": "21.1.262",
     "neoForgeRange": "[21.1,21.2)",
     "nativeAccess": "minecraft1_21_1",
+    "testLoaders": [
+      "fabric",
+      "neoforge"
+    ],
     "fabricModules": {
       "fabric-api-base": "0.4.42+6573ed8c19",
       "fabric-registry-sync-v0": "5.3.2+e3eddc2119",