feat(async): Add django-q2 with ORM broker and demo job

[taylor-osler-sentry]

Summary

• Adds django-q2 as a dependency and configures it with the ORM broker (backed by the existing PostgreSQL default database)
• Introduces firetower.incidents.tasks.schedule_demo as the first queue task
• Introduces a wrapped_worker command that starts the cluster worker with health checking
  • Note: this requires django-cache, which is also set up in this PR
• Includes datadog function wrapper for metrics

Test plan

• Run python manage.py migrate — confirm 0016_schedule_demo applies cleanly and a schedule_demo row appears in django_q_schedule
• Run python manage.py wrapped_worker — confirm the worker starts and picks up the scheduled task
• Run docker/entrypoint.sh migrate — confirm the container runs the cache table migration as well
• Run docker/entrypoint.sh worker — confirm the container starts the qcluster process

🤖 Generated with Claude Code

[linear-code]

RELENG-538 Stand up some kind of async task running capability for Firetower

RELENG-562

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[cursor]

raise e corrupts traceback in decorator wrapper

Low Severity

Using raise e instead of bare raise in the datadog_log exception handler adds an extra frame to the traceback, making it appear the exception originated from the decorator wrapper rather than the actual task function. This makes debugging task failures harder since the traceback points to the wrong location.

 

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