Add SWBWebAssemblyPlatformPlugin

This mirrors the other platforms.

Author: mhrawdon

Sources/SWBWebAssemblyPlatformPlugin/PluginMain.swift

@@ -0,0 +1,20 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SWBUtil
+import SWBCore
+import SWBWebAssemblyPlatform
+
+@_cdecl("initializePlugin")
+@PluginExtensionSystemActor public func main(_ ptr: UnsafeRawPointer) {
+    initializePlugin(Unmanaged<PluginManager>.fromOpaque(ptr).takeUnretainedValue())
+}