feat(core): add @choojs/core — ESM port of choo with consolidated nano* internals

Same public API as choo 7.1.0 (use/route/start/mount/toString/emit; choo()
callable with or without new, Choo exported). nanobus, nanorouter+wayfarer,
nanolru+component cache, nanoraf, nanohref, nanotiming, document-ready and
scroll-to-anchor are ported into lib/ with per-file attribution; nanoquery
is replaced by URLSearchParams. The v7 node test suite is ported from tape
to node:test and passes unchanged in behavior.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014NgfSjHE11oFpoSnLVKLXd

packages/core/lib/query.js

@@ -0,0 +1,23 @@
+// Replaces nanoquery 1.3.0 (MIT) with the platform's URLSearchParams.
+// Semantics preserved: returns a plain object; repeated keys become arrays.
+
+import { equal } from './assert.js'
+
+export default function nanoquery (url) {
+  equal(typeof url, 'string', 'nanoquery: url should be type string')
+
+  const query = {}
+  const index = url.indexOf('?')
+  if (index === -1) return query
+
+  const params = new URLSearchParams(url.slice(index + 1))
+  for (const [key, value] of params) {
+    if (Object.hasOwn(query, key)) {
+      if (Array.isArray(query[key])) query[key].push(value)
+      else query[key] = [query[key], value]
+    } else {
+      query[key] = value
+    }
+  }
+  return query
+}