Audit: concurrent-connection behavior in the Node adapter

[smiggleworth]

Purpose

Audit task, not a bug report — produces a test matrix, doesn't fix anything.

Procedure

Write or locate tests exercising genuinely concurrent connections/requests through the adapter:

• Many simultaneous requests hitting the static-asset guard (Static asset routing silently shadows dynamic routes with dotted paths; duplicated content-type parsing #28) at once, including a mix of dotted-path dynamic routes and real static files
• Concurrent requests where one connection is aborted mid-response while others continue
• Socket-level backpressure: a slow client alongside fast ones
• Server startup/shutdown racing with in-flight requests

Definition of Done

• Table: scenario | ✅ test exists and passes / 🔗 gap filed.
• No row left unmarked.

Audit results (2026-08-24)

Scenario	Evidence	Result
Concurrent real assets plus dotted and percent-encoded dynamic routes	tests/node.test.ts — should let excluded dotted routes bypass static serving under concurrency	✅
One connection aborts mid-request while other work continues	should abort the Web Request when the Node request closes; shared real-socket conformance test	✅
Slow/backpressured response alongside normal transport behavior	should honor response backpressure; full concurrent suite	✅
Shutdown races with an in-flight request	should wait for an in-flight request before completing shutdown	✅
Concurrent shutdown callers	should close the application exactly once across concurrent shutdown	✅

New coverage is included in #35; no concurrency defect remained.

[smiggleworth]

Completed by #35, with the shared media-type helper exposed by askrjs/askr-server#44. The full local gate and hosted Ubuntu/macOS/Windows CI passed; no package was bumped or published.