perf: faster dev startup and lighter bundle

- Switch dev default to Turbopack (5-14x faster compile); keep webpack as dev:webpack
- Tailwind v4 source() base so JIT scans identically under both bundlers
- Lazy-load @xyflow/react via next/dynamic to keep it out of the shared bundle
- optimizePackageImports for heavy barrel imports (xyflow, dnd-kit, material-symbols, marked)
- Replace blind setTimeout waits with TCP health-check (waitServerReady)
- Run checkForUpdate in parallel instead of blocking server spawn
- Background MITM/tunnel/cloudflared kills off the critical path

Co-authored-by: Cursor <cursoragent@cursor.com>

package.json

@@ -4,7 +4,8 @@
   "description": "9Router web dashboard",
   "private": true,
   "scripts": {
-    "dev": "next dev --webpack --port 20127",
+    "dev": "next dev --port 20127",
+    "dev:webpack": "next dev --webpack --port 20127",
     "build": "next build --webpack",
     "start": "next start --port 20127",
     "dev:bun": "bun --bun next dev --webpack --port 20127",