add WASM blazor-like thing

go/wasmruntime/wasmruntime.go

@@ -0,0 +1,7 @@
+//go:build !(js && wasm)
+
+// Package wasmruntime is the browser-side client runtime (reconciler, mount /
+// hydrate, router, fetch, hot-reload state preservation). Its implementation
+// compiles only under GOOS=js GOARCH=wasm; this placeholder keeps the package
+// non-empty on other platforms so `go build ./...` / `go vet ./...` succeed.
+package wasmruntime