Rebrand LegacyForge to Weave Loader

Rename across entire codebase:
- LegacyForge -> WeaveLoader (identifiers, namespaces, classes, DLLs)
- LegacyForgeRuntime -> WeaveLoaderRuntime (C++ project)
- LegacyForge.API/Core/Launcher -> WeaveLoader.API/Core/Launcher (C# projects)
- [LegacyForge] -> [WeaveLoader] (log prefixes)
- legacyforge -> weaveloader (config files, log files, backup suffixes)
- Display name "Weave Loader" in README, CONTRIBUTING, LICENSE

WeaveLoader.Core/WeaveLoader.Core.runtimeconfig.json

@@ -0,0 +1,10 @@
+{
+  "runtimeOptions": {
+    "tfm": "net8.0",
+    "rollForward": "LatestMinor",
+    "framework": {
+      "name": "Microsoft.NETCore.App",
+      "version": "8.0.0"
+    }
+  }
+}