test: cover URL canonicalization utilities

[saurabhhhcodes]

Summary

• add Jest coverage for canonicalizePathname, canonicalEndpoint, and normalizeUrl
• cover numeric IDs, UUIDs, high-entropy path segments, root path handling, method normalization, and query/hash stripping

Fixes #3

Validation

• git diff --check
• node --check tests/utils/canonicalize.test.js
• npm test -- --runInBand could not run locally because npm is not available in this shell

GSSoC labels requested

Please add/keep gssoc and the required difficulty/type scoring labels if this is accepted.

[saurabhhhcodes]

Closing this older version to keep the review queue clean. The current replacement for URL canonicalization coverage is #28.