fix(server): send large test case lookups as multipart

Summary

• Fix the self-hosted test ingestion path where large existing-test-case lookups can exceed request header limits.
• Keep the lookup on Ecto primitives and pass multipart: true to ClickHouseRepo.all/2, so ecto_ch keeps handling UUID, boolean, datetime, and array decoding.
• Add a regression test that builds a 5,001-test-case payload and asserts the lookup uses multipart transport for both chunks.

Testing

• mix format lib/tuist/tests.ex test/tuist/tests_test.exs
• MIX_ENV=test mix compile
• mix test test/tuist/tests_test.exs:1175 (blocked during test DB setup: 20240415140351_create_users_auth_tables.exs tries to create users_tokens before a users table exists, raising ERROR 42P01 (undefined_table) relation "users" does not exist)

No GitHub comments yet.