Initial commit: LegacyForge mod loader for Minecraft Legacy Edition

SKSE-style external mod loader with zero game source modifications.
- LegacyForge.Launcher: C# console app that injects runtime DLL into game process
- LegacyForgeRuntime: C++ DLL with PDB symbol resolution, MinHook function hooking, and .NET CoreCLR hosting
- LegacyForge.Core: C# mod discovery and lifecycle management
- LegacyForge.API: Fabric-style mod API with namespaced string IDs, fluent property builders, and event system
- ExampleMod: Sample mod demonstrating block/item registration

README.md

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+# LegacyForge
+
+An SKSE-style mod loader for Minecraft Legacy Edition. LegacyForge injects into the game process at runtime, hooks key engine functions, and hosts the .NET runtime to load C# mods. **Zero game source modifications required.**
+
+## How It Works
+
+1. **LegacyForge.exe** launches the game in a suspended state and injects `LegacyForgeRuntime.dll`
+2. The runtime DLL uses PDB debug symbols to locate game functions (`MinecraftWorld_RunStaticCtors`, `Minecraft::tick`, etc.)
+3. MinHook detours those functions to insert mod lifecycle callbacks
+4. The .NET CoreCLR runtime is hosted inside the game process via hostfxr
+5. `LegacyForge.Core` discovers and loads C# mod assemblies from the `mods/` folder
+6. Mods use the `LegacyForge.API` to register blocks, items, entities, and subscribe to game events using Fabric-style namespaced string IDs
+
+## Project Structure
+
+```
+ModLoader/
+├── LegacyForge.Launcher/       C# launcher (the exe users run)
+├── LegacyForgeRuntime/          C++ DLL (injected into game process)
+├── LegacyForge.Core/            C# mod management (loaded inside game)
+├── LegacyForge.API/             C# mod API (what mod authors reference)
+└── ExampleMod/                  Sample mod for reference
+```
+
+## Building
+
+### Prerequisites
+
+- Visual Studio 2022 or later (with C++ and .NET workloads)
+- .NET 8.0 SDK or later
+- CMake 3.24 or later
+- The game must be compiled with PDB generation
+
+### Build Steps
+
+**C++ Runtime DLL:**
+
+```bash
+cd LegacyForgeRuntime
+cmake -B build -A x64
+cmake --build build --config Release
+```
+
+**C# Projects:**
+
+```bash
+dotnet build LegacyForge.sln
+```
+
+## Usage
+
+1. Build LegacyForge (see above)
+2. Copy the output files to a folder:
+   - `LegacyForge.exe`
+   - `LegacyForgeRuntime.dll`
+   - `LegacyForge.Core.dll`
+   - `LegacyForge.API.dll`
+3. Create a `mods/` folder and drop mod DLLs in it
+4. Run `LegacyForge.exe` -- it will ask for the game exe path on first launch
+5. The game starts with mods loaded
+
+## Writing a Mod
+
+Create a new .NET 8 class library and reference `LegacyForge.API`:
+
+```csharp
+using LegacyForge.API;
+
+[Mod("mymod", Name = "My Mod", Version = "1.0.0", Author = "You")]
+public class MyMod : IMod
+{
+    public void OnInitialize()
+    {
+        var myBlock = Registry.Block.Register("mymod:cool_block",
+            new BlockProperties()
+                .Material(MaterialType.Stone)
+                .Hardness(2.0f)
+                .Resistance(10f));
+
+        Logger.Info("My Mod loaded!");
+    }
+}
+```
+
+Build it, copy the DLL to `mods/`, and launch via LegacyForge.
+
+## License
+
+[MIT](LICENSE)