Improve Insomnia endpoint extraction

[hahwul]

Summary

• filter Insomnia v5 non-HTTP URL nodes to reduce endpoint false positives
• extract query/path/auth parameters from v4/v5 exports, including nested env vars and templated path params
• add Insomnia edgecase fixture coverage, including TRACE support from the shared HTTP method list

Verification

• crystal spec --error-trace spec/functional_test/testers/specification/insomnia_spec.cr
• just build
• just check

Notes

• just test unit phase passed, but the functional phase hung locally for 12+ minutes in existing Python Flask apply_nested_blueprint_prefixes; I terminated the stuck local process after sampling it. This appears unrelated to the Insomnia changes.