Add OpenUI Cloud build telemetry

[zahlekhan]

What changed

• add a compiler.runAfterProductionCompile hook to the OpenUI Cloud Next.js template
• generate a random project-scoped telemetry ID only when CLI telemetry is enabled
• attach that project ID to the existing scaffold funnel and the compiler event
• send an allowlisted, best-effort PostHog event with a one-second timeout
• disable PostHog person profiles and geo-IP enrichment for the compiler event
• document the event semantics, collected fields, and opt-out controls
• add coverage for payload privacy, stable identity, opt-outs, malformed metadata, offline behavior, and timeouts

Why

The existing CLI telemetry measures scaffolding and OIDC authentication, but it does not show whether a generated OpenUI Cloud project reaches production compilation. This adds a directional activation signal without wrapping package-manager build scripts or collecting project code, paths, prompts, API keys, environment values, or build output.

The event is named openui_template_production_compile_completed. It intentionally does not claim that the overall build succeeded because Next.js runs this hook before type checking and static generation.

Projects created with --no-telemetry, DO_NOT_TRACK=1, or OPENUI_TELEMETRY_DISABLED=1 do not receive a project marker. Existing generated projects also honor both environment opt-outs at build time.

Validation

• pnpm --dir packages/openui-cli run ci
• 8 build-telemetry tests passing
• generated Next.js 16.1.6 production build completed successfully with the hook running between compilation and TypeScript
• npm package dry run confirmed the hidden template helper is included in the published CLI artifact