Fix execute wait false timeouts and active HTTP session reaping

[cursor]

Description

Fixes two high-severity execute-wait correctness issues:

• harness_execute(..., wait=true) no longer reports execution_timed_out=true when polling gives up after five consecutive execution.get errors before the configured timeout expires. It now fails the wait path so callers see _wait.error while preserving the successful trigger response.
• HTTP Streamable sessions now track active requests and the idle reaper skips sessions with in-flight POST/SSE requests, preventing long waits (up to the documented 7200s) from being closed by the 30-minute session TTL.

Added focused regression coverage for both behaviors and recorded the inspection in tasks/todo.md.

Type of Change

• Bug fix
• New feature
• Refactor
• Documentation
• Other

Checklist

• Tests pass
• Typecheck passes

Validation:

• pnpm test tests/utils/poll-execution.test.ts tests/integration/http-transport.test.ts
• pnpm typecheck
• pnpm build
• pnpm test (59 files / 1400 tests)
• Independent code review subagent: no blocking issues found

  

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