Phase 10: implement neoforge-26_1 leaf (WS, deltas, chat, link, reconciliation, player tracking)

Ports the full feature set proven by the two legacy leaves to modern, post-Flattening
NeoForge (loader assumption confirmed: NeoForge 26.1.2.94 is real and published).
Neoforge261ChunkAdapter reads BlockState via LevelChunk/LevelChunkSection instead of raw
id+meta, carrying the full packed state id in DeltaEvent#blockStateId (a lossless int,
unlike the pre-Flattening 16-bit encoding) while documenting a known truncation caveat for
SectionData's char[]-based 3D backfill on very large modded registries. MCMapperMod uses
constructor-injected event buses (IEventBus/ModContainer) and NeoForge.EVENT_BUS instead of
@Mod.EventHandler methods, ModConfigSpec instead of legacy Configuration, and LinkCommand is
a Brigadier registration (no CommandBase in this era) fired from RegisterCommandsEvent.
Tracks its own loaded-chunk set via ChunkEvent.Load/Unload rather than querying chunk
provider internals (no stable public API for that in modern MC).

Gets its own standalone Gradle wrapper + settings.gradle (Foojay toolchain resolver) since
ModDevGradle needs Gradle 8+ and a Java 25 toolchain (MC itself now requires Java 25),
incompatible with the legacy leaves' Gradle-7/JDK-8 pin in one invocation.

Verified against real NeoForge 26.1.2.94 + decompiled MC 26.1.2 source via
./gradlew build from inside neoforge-26_1/ (two real API mismatches caught and fixed by
the compiler: ChunkPos is now a record — x()/z() methods, not fields — and
ResourceLocation was renamed to Identifier, ResourceKey#identifier() not #location()).

neoforge-26_1/settings.gradle

@@ -0,0 +1,25 @@
+// Standalone build — deliberately NOT part of the root multi-project build (see the root
+// settings.gradle's comment): ModDevGradle needs Gradle 8+ and a Java 25 toolchain, incompatible
+// with the two legacy leaves' Gradle-7/JDK-8-daemon pin within one Gradle invocation. Build this
+// leaf from inside this directory, with its own wrapper:
+//
+//   cd neoforge-26_1 && ./gradlew build
+//
+// The Gradle daemon itself can run on any modern JDK on PATH/JAVA_HOME (8.14.x supports up to
+// JDK 23 as the *daemon* JVM) — it does not need to already be JDK 25. The Foojay resolver below
+// lets Gradle auto-provision an actual JDK 25 toolchain (into its own GRADLE_USER_HOME cache, not
+// a system-wide install) for the compile/run tasks that require Minecraft's own Java 25
+// requirement, without needing one pre-installed.
+pluginManagement {
+    repositories {
+        gradlePluginPortal()
+        maven { url = 'https://maven.neoforged.net/releases' }
+        mavenCentral()
+    }
+}
+
+plugins {
+    id 'org.gradle.toolchains.foojay-resolver-convention' version '0.8.0'
+}
+
+rootProject.name = 'neoforge-26_1'