perf(dev): Optimize dev server boot time
- Extract dev server initialization to separate module (dev-server-init.ts)
for better code organization and lazy loading
- Defer TypeScript verification to run in background instead of blocking startup
- Fix timing accuracy: "Ready in Xms" now includes CLI start, fork overhead,
and IPC handshake (~140ms previously hidden from users)
- Pass NEXT_CLI_START_TIME from parent to child process for accurate measurement
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
