test(replay): add pairFramesStreamed unit tests

[protosphinx]

Why

pairFramesStreamed is the function that powers SSE multi-frame replay (v0.4.1). It is only exercised indirectly by the HTTP integration tests in test/http.sse.test.ts, which spin up a real HTTP server and hit it over the network. A dedicated unit suite lets us verify the pairing logic directly against Frame arrays, covering edge cases the integration test does not reach.

What

• Add pairFramesStreamed to the import in test/replay.test.ts
• Add a new describe("pairFramesStreamed") block with 5 focused tests:
  • single response wrapped in a one-element array (non-streaming baseline)
  • multiple response frames collected for one streaming request (progress + result)
  • collection stops at the next outbound request (boundary condition)
  • requests with no responses are excluded from the result
  • server-pushed notifications (no id) are included in the response list

Tests

• npm test runs all 14 test files; all 158 tests pass including the 5 new ones
• No source changes, no new dependencies

Self-merge gate

• all CI checks pass
• LOC delta < 250 (126 lines added/removed)
• no public-API surface change
• no runtime-dependency additions
• no workflow file changes
• tests added or extended

---

Generated by Claude Code