Add a smoke test workflow that runs against py-amqp, Kombu and Billiard main

[GangEunzzang]

Closes #10675.

Adds .github/workflows/smoke-tests-dev.yml, a separate workflow on the same push/PR triggers as the main one. It calls the reusable smoke-tests.yml with a new dev_requirements input, which selects the smoke-dev tox env: the smoke env plus requirements/dev.txt, so the host gets py-amqp, Kombu and Billiard from Git main. That env also sets CELERY_DEV_REQUIREMENTS=1, which SmokeWorkerContainer.buildargs() passes to the worker image, where a new build arg installs dev.txt on top of the editable Celery install. Without the flag the image build is unchanged, and python-package.yml is untouched.

The job covers test_worker.py and test_tasks.py (the two files that caught the Billiard 4.3.0 changes in #10659) on one Python version, so it is two extra jobs rather than another full matrix.

Checked locally on macOS with Docker: the 3.12-smoke-dev tox env ends up with py-amqp, Kombu and Billiard from Git (direct_url.json points at the three repos), the worker image does too with the build arg and stays on PyPI without it, and both files pass in that mode (test_tasks.py 22 passed, test_worker.py 62 passed / 6 skipped, same as with the released versions).

Two things worth knowing. The image install needs --force-reinstall: pip clones the three repos but keeps the PyPI copy when the checkout reports the same version string. And default.txt pins billiard==4.3.0, so once Billiard main bumps its version the dev job will fail at install time until the pin moves, which is the kind of thing this job exists to surface.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.28%. Comparing base (7b4edf4) to head (24ce861).

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #10676   +/-   ##
=======================================
  Coverage   89.28%   89.28%           
=======================================
  Files         153      153           
  Lines       20397    20397           
  Branches     2431     2431           
=======================================
  Hits        18212    18212           
  Misses       1881     1881           
  Partials      304      304           

Flag	Coverage Δ
unittests	89.26% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

[auvipy]

i can not see the jobs, can you please point me to them?

[GangEunzzang]

They run as a separate workflow, "Smoke Tests (dev requirements)": https://github.com/celery/celery/actions/runs/35589666299 — four jobs, test_tasks.py and test_worker.py on 3.14 and 3.15. The test_tasks.py ones have already passed, the test_worker.py ones are still running. They also show up under the PR's checks as Smoke-tests-dev (...).

[auvipy]

things are passing here but the kombu 5.7.0a1 compatibility check pr got some failures here #10677