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.API/ModAttribute.cs

@@ -0,0 +1,41 @@
+namespace WeaveLoader.API;
+
+/// <summary>
+/// Marks a class as a WeaveLoader mod and provides metadata.
+/// The class must also implement <see cref="IMod"/>.
+/// </summary>
+[AttributeUsage(AttributeTargets.Class, AllowMultiple = false, Inherited = false)]
+public sealed class ModAttribute : Attribute
+{
+    /// <summary>
+    /// The unique mod identifier (e.g. "examplemod"). Used as the default namespace
+    /// for content registered by this mod.
+    /// </summary>
+    public string Id { get; }
+
+    /// <summary>
+    /// Human-readable display name.
+    /// </summary>
+    public string Name { get; set; } = "";
+
+    /// <summary>
+    /// Semantic version string (e.g. "1.0.0").
+    /// </summary>
+    public string Version { get; set; } = "1.0.0";
+
+    /// <summary>
+    /// Mod author(s).
+    /// </summary>
+    public string Author { get; set; } = "";
+
+    /// <summary>
+    /// Short description of the mod.
+    /// </summary>
+    public string Description { get; set; } = "";
+
+    public ModAttribute(string id)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(id);
+        Id = id;
+    }
+}