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

packages/devtools/package.json

@@ -0,0 +1,22 @@
+{
+  "name": "@choojs/devtools",
+  "version": "8.0.0-dev",
+  "description": "Console devtools for choo: window.choo, event log, perf timings",
+  "type": "module",
+  "exports": {
+    ".": "./index.js"
+  },
+  "files": [
+    "index.js"
+  ],
+  "engines": {
+    "node": ">=24"
+  },
+  "repository": "choojs/choo",
+  "keywords": [
+    "choo",
+    "devtools",
+    "debug"
+  ],
+  "license": "MIT"
+}