openwebf-host-performance-metrics

在Flutter中使用WebF性能工具（FP/FCP/LCP，dumpLoadingState，加载状态事件）进行性能诊断。当用户提到FP/FCP/LCP、dumpLoadingState、首次渲染慢、LCP验证或性能监控时使用。

OpenWebF Host: Performance Metrics & Diagnosis

Establish measurement: capture FP/FCP/LCP and key lifecycle timings.
Use MCP docs for the official performance monitoring APIs and guidance.
Use dumpLoadingState (or equivalent) to diagnose where time is spent.
Offer scaffolding templates when useful:
- perf/loading-state-events
- perf/loadingstate-dump
- perf/lcp-content-verification