fix: normalize method in findRoute

[Ram-blip]

Description

findRoute() was passing the provided method directly to the router lookup. Because registered route methods are normalized, a lookup like findRoute({ method: 'get', ... }) returned null even when the matching GET route existed.

This change normalizes the method in findRoute(), matching the existing behavior in hasRoute().

Changes proposed:

• Updated lib/route.js to normalize the method before calling router.find()
• Added a regression test in test/find-route.test.js for lowercase method lookup

Verification

1. Ran node --test test/find-route.test.js
2. Ran node --test test/has-route.test.js
3. Ran npm test

Checklist

• run npm run test && npm run benchmark --if-present
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct