feat(devtools): add @choojs/devtools — window.choo console tooling

Carries forward the choo-devtools 3.x essentials: live state handle,
emit-from-console, event log, nanotiming measures via PerformanceObserver,
state copy(), help(). No-op on the server; verbose logging opt-in via
localStorage.CHOO_DEVTOOLS_VERBOSE.

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

package.json

@@ -11,7 +11,7 @@
     "node": ">=24"
   },
   "scripts": {
-    "test": "node --test packages/core/test/ packages/html/test/ packages/component/test/",
+    "test": "node --test packages/core/test/ packages/html/test/ packages/component/test/ packages/devtools/test/ packages/migrate/test/",
     "test:e2e": "node --test test/e2e/",
     "bench": "node bench/render.js",
     "bench:browser": "node bench/real-browser.js"