feat(rate-limit): make trustProxy configurable in keyGenerator default

[tada5hi]

Pre-existing issue found during PR review

Reported in: PR #766, review comment by @coderabbitai[bot]
File: packages/rate-limit/src/utils/options.ts#19

Description

The default keyGenerator hardcodes trustProxy: true when calling getRequestIP():

keyGenerator: (event) => getRequestIP(event, { trustProxy: true }) || '127.0.0.1',

This enables inspection of forwarded headers (X-Forwarded-For) by default, which could allow clients to spoof IPs and evade rate limiting in non-proxied or misconfigured deployments.

This has been the default behavior since v1 and was carried through the v5 migration in PR #766.

Suggested fix

1. Add a trustProxy boolean field to the Options type (default false)
2. Update the default keyGenerator to use options.trustProxy instead of hardcoded true
3. Update README documentation to reflect the new option