feat(dll): add hot-injection DLL path with embedded GUI loader

Ship a self-contained OpenZenLoader.exe (OpenZen.dll embedded as
RCDATA) that injects into a running Minecraft 1.20.1 Forge
javaw.exe and brings up the Zen client without -javaagent or a
mods/ entry. The existing Forge mod path stays intact.

Native (native/):
  - DLL: JNI_GetCreatedJavaVMs + JVMTI late-attach via the JDK's
    instrument.dll Agent_OnAttach to obtain a real Instrumentation;
    URLClassLoader on the game loader loads a single bridge class.
  - Loader EXE: Win32 listview of javaw.exe/java.exe processes
    with window titles, CreateRemoteThread+LoadLibraryW injection,
    embedded DLL extracted to %TEMP%\OpenZenLoader at runtime.

Java:
  - shit.zen.dll.GameLoaderBridge re-defines every jar class onto
    the Forge GameClassLoader (fixed-point retry for super-class
    deps) and extracts non-class resources to
    %TEMP%\openzen-resources-<pid>, exposed via the
    openzen.resources system property.
  - shit.zen.dll.DllBootstrap only runs Bootstrap.init +
    registerPatches + installPatchesAndRetransform; ZenClient
    construction stays on MinecraftPatch.onTick lazy-init.
  - shit.zen.asm.Bootstrap parses mapping.srg, detects SRG vs
    mojmap runtime via Minecraft.tick reflection, exposes
    remapMethod/remapField used at 5 PatchTransformer match
    points and from ReflectionUtil.
  - ReflectionUtil.resolveField walks the superclass chain trying
    SRG then mojmap on each level so e.g. activeEffects on
    LocalPlayer resolves on LivingEntity.
  - shit.zen.utils.misc.Assets unifies resource lookup with a
    fallback to openzen.resources; fonts, cloud assets and WebUI
    static files route through it.
  - PatchAgent.installPatchesAndRetransform is now idempotent so
    DllBootstrap and ZenClient.init can both call it safely.

Build:
  - ./gradlew jar   forge mod jar (unchanged)
  - ./gradlew dll   single-file Loader EXE in build/dist
  - CMake auto-located via vswhere when VS 2022 ships it.
  - README documents both paths and required toolchain.

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

.gitignore

@@ -23,3 +23,7 @@ run
 
 # Files from Forge MDK
 forge*changelog.txt
+
+# Native DLL build artifacts (CMake out-of-source build + staged jar)
+native/build/
+native/zen.jar