Fix retryable task tests by correcting decorator composition and per-test retry counter setup

[Copilot]

test_retryable_task_throws and test_retryable_task_throws_retry regressed due to decorator composition that returned plain functions (losing .delay()), plus retry counter state initialized at module load. This updates test task construction so Celery wrapping remains outermost and retry counting is initialized per test instance.

• Decorator composition (Celery task integrity)

  • Ensure @count_retries is applied to the raw function, with @retryable_task() outermost, so the exported object is still a Celery task and supports .delay().

• Retry counter isolation

  • Move thread_data.retry_count initialization out of decorator definition time and into task factory functions used by each test.
  • Eliminate shared module-load initialization side effects between tests.

• Counter semantics cleanup

  • Simplify count_retries to increment from 0 by +1 per invocation.
  • Update wrapper to pass through *args/**kwargs and return the wrapped function result.

• Test task setup updates

  • Replace module-level throwing task declarations with create_throwing_task() and create_throwing_task_should_retry() factories.
  • Align assertions with explicit per-call counting.

def create_throwing_task():
    thread_data.retry_count = 0

    @retryable_task()
    @count_retries
    def throwing_task():
        raise TypeError

    return throwing_task

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[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.85%. Comparing base (050fedf) to head (e69b920).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #9845   +/-   ##
=======================================
  Coverage   83.85%   83.85%           
=======================================
  Files         643      643           
  Lines       39269    39276    +7     
  Branches     3502     3502           
=======================================
+ Hits        32929    32936    +7     
  Misses       5950     5950           
  Partials      390      390           

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