Release queue message context after processing

[abnegate]

Summary

• release the per-coroutine dependency context only after message, commit or reject, and outcome callbacks finish
• collect cyclic objects and allocator caches at the queue-owned message boundary
• preserve wait-group and coroutine-slot release when cleanup, observation, or diagnostic output fails

This supplies the lifecycle boundary needed by Appwrite DAT-2477 and appwrite/cloud#5487. It does not release this package, update Cloud dependency resolution, merge, or deploy anything.

Verification

• regression observed red on the original head: 5 failures
• focused lifecycle suite: 5 tests, 33 assertions
• queue unit tier: 78 tests, 250 assertions
• platform linked tier: 11 tests, 90 assertions
• bin/monorepo validate
• bin/monorepo check queue --fix

The Docker-backed queue E2E tier could not start locally because the active Docker daemon socket did not answer its health ping. CI remains fail-closed for that lane.