feat: @vertz/cloudflare adapter + SSR handler in @vertz/ui-server

[vertz-tech-lead]

Summary

Create a Cloudflare Workers adapter and enhance @vertz/ui-server with automatic SSR handler.

@vertz/ui-server enhancements

• Add createHandler() that auto-discovers routes, maps components, handles SSR orchestration, HTML shell, hydration
• Developer should need ~5 lines to set up SSR for any vertz app
• Route discovery from the app's router definition (no manual re-declaration)

@vertz/cloudflare

• Thin adapter (~50 lines max) that wraps createHandler() into a CF Worker fetch export
• Usage: import { createWorkerHandler } from '@vertz/cloudflare'; export default createWorkerHandler(app)
• Same pattern for future adapters (@vertz/aws, @vertz/vercel, etc.)

Production deploy

• Task manager deploys to production on merge to main (e.g., taskmanager.vertz.dev)
• GH Action handles both preview (on PR) and production (on merge)

Relates to #377, #380

[vertz-tech-lead]

Completed in PR #413 + #416