preserve Gantt tooltip task end date

[mralonsocorona]

Why

Fixes #68174.

The Gantt timeline splits a task instance into visual segments such as scheduled, queued, and execution. For queued segments, the visual segment ends at start_date, which is correct for rendering the queued portion of the bar.

However, the tooltip summary used the visual segment end (segment.x[1]) as max_end_date. This caused the queued segment tooltip to show the end of the queued interval as the task End Date, instead of the real task instance end_date.

What changed

• Preserve the real task instance end_date on each Gantt segment as end_when.
• Use segment.end_when for the tooltip max_end_date when available.
• Keep the existing visual segment boundaries unchanged.
• Add unit test coverage to ensure queued and execution segments retain the real task end date.

Testing

• git diff --check
• cd airflow-core/src/airflow/ui && pnpm test src/layouts/Details/Gantt/utils.test.ts

Result:

• 1 test file passed
• 15 tests passed

[boring-cyborg]

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[pierrejeambrun]

Thanks for the PR but unfortunately #68570 is closer to getting meerged and more complete (test cases, handling running TI logic, etc...)

Closing, feel free to re-open if I missed something.

[mralonsocorona]

Thanks for the review and for the context. That makes sense — #68570 covers the same issue more completely, including the running task instance case.

Closing this PR is fine from my side. I’ll follow #68570 and look for another issue to help with.