Refactor web adapter to universal adapter

Rename the web adapter to universal adapter to better reflect its
framework-agnostic nature. This change involves updating package.json,
file paths, and documentation.

app/build.ts

@@ -331,7 +331,7 @@ async function buildAdapters() {
     }),
 
     tsup.build({
-      ...baseConfig("web"),
+      ...baseConfig("universal"),
       platform: "neutral",
     }),