Add e2e tests for HTTP behavior consistency

[jmg-duarte]

Description

Add e2e tests to verify HTTP behavior consistency before the warp-to-axum migration.

Changes

• Add cors.rs - Tests for CORS preflight requests and CORS headers on error responses
• Add missing_endpoints.rs - Tests that invalid/nonexistent routes return 404
• Add malformed_requests.rs - Tests for:
  • Malformed path parameters (OrderUid, Address, B256, AuctionId) return 404
  • Malformed request bodies (invalid JSON, empty body, missing fields, wrong types) return 400
  • Error response format verification (deserialization errors return plain text, business logic errors return JSON with errorType and description)

How to test

Run the new e2e tests:

cargo nextest run -p e2e cors --run-ignored ignored-only --test-threads=1 --failure-output final
cargo nextest run -p e2e missing_endpoints --run-ignored ignored-only --test-threads=1 --failure-output final
cargo nextest run -p e2e malformed_requests --run-ignored ignored-only --test-threads=1 --failure-output final

[gemini-code-assist]

Code Review

This pull request adds end-to-end tests for HTTP behavior consistency. The assertions in the CORS preflight tests are not sufficiently strict, as they use substring checks on comma-separated header values. This can result in false positives. I have suggested replacing these with more robust checks that parse the header values and verify exact matches to ensure test reliability.

[MartinquaXD]

Looks alright to me. Judging by the tests a reasonable rule of thumb seems to be:
can't find path or parse the URL components => 404
URL parses find but body is malformed => 400

[jmg-duarte]

Looks alright to me. Judging by the tests a reasonable rule of thumb seems to be:
can't find path or parse the URL components => 404
URL parses find but body is malformed => 400

Yeah because a malformed path is basically a non-existing one, I think it makes more sense like this