[Aryan9891]

Description

This PR documents the behavior of DAG schedule intervals and DagRun generation during Daylight Saving Time (DST) transitions in airflow-core/docs/authoring-and-scheduling/timezone.rst, addressing the confusion around skipped/gap and folded/repeated hours in timezone-aware DAG schedules.

Specifically, it clarifies:

• Spring Forward (Entering DST - Non-existent wall-clock times): How non-existent wall-clock times (e.g. 02:00-03:00) are bridged by Airflow's cron interval timetable by ending the data interval at the newly advanced local time (aligned to the DST switch point in UTC), resulting in a 23-hour transition data interval while ensuring DagRuns are created normally without being dropped.
• Fall Back (Exiting DST - Repeated wall-clock times): How repeated wall-clock times (e.g. 01:00-02:00) are disambiguated using the fold=1 attribute, resulting in a 25-hour transition data interval and generating a single DagRun across the fold rather than duplicating runs for the same wall-clock timestamp.
• Elapsed Time Recommendations: Guidance to use UTC (tz="UTC" or schedule=timedelta(...)) when workflows require strictly uniform, constant physical elapsed intervals.

closes: #38098

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Was generative AI tooling used to co-author this PR?

• Yes (Antigravity)

Generated-by: Antigravity following the guidelines

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[boring-cyborg]

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