make trpc-nuxt flexible by exporting server and client functions instead of nuxt modules

tsup.config.ts

@@ -0,0 +1,10 @@
+import { defineConfig } from 'tsup'
+
+export default defineConfig({
+  entry: ['src/index.ts', 'src/client.ts'],
+  format: ['cjs', 'esm'],
+  splitting: false,
+  clean: true,
+  external: ['#app'],
+  dts: true,
+})