perf: establish lifecycle baselines

[okyrychenko-dev]

Summary

• add repeatable production-build benchmarks for provider mounting and unmounting
• measure modal opening, rendering, settlement, delayed removal, stacked instances, and typed registry routing
• separate setup and warmup operations from timed measurements
• report environment metadata, raw samples, and min/mean/p50/p95/max summaries
• measure delayed removal until the rendered modal is actually removed from the DOM
• add pnpm run benchmark:lifecycle as the reproduction command
• introduce no public API changes, performance thresholds, or comparison claims

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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