Fix task duration chart rendering issues in Airflow 3

[abhijeets25012-tech]

Description

Fixes #63582

The task duration chart in Airflow 3 had several rendering issues
compared to Airflow 2. This PR addresses all of them.

Changes Made

1. Chart Size

• Added w="100%" to make chart full width
• Added h="400px" fixed height wrapper
• Added maintainAspectRatio: false so chart respects height

2. Y-Axis Units

• Changed from HH:MM:SS format to human readable s/m/h
• Example: now shows 30s, 5.2m, 1.5h instead of 00:00:30

3. Median Duration Line

• Added median() function to calculate median value
• Added blue dashed reference line showing median total duration
• Label displays the median value at end of line

4. Legend

• Added Legend to Chart.js imports and registration
• Added legend: { display: true, position: "top" } to options
• Users can now see what each color represents

Screenshots

Testing

• Built successfully with npm run build
• All 4301 modules transformed without errors

Related Issue

Closes #63582

[potiuk]

@abhijeets25012-tech This PR has been converted to draft because it does not yet meet our Pull Request quality criteria.

Issues found:

• ❌ Pre-commit / static checks: Failing: CI image checks / Static checks. Run prek run --from-ref main locally to find and fix issues. See Pre-commit / static checks docs.

Note: Your branch is 56 commits behind main. Some check failures may be caused by changes in the base branch rather than by your PR. Please rebase your branch and push again to get up-to-date CI results.

What to do next:

• The comment informs you what you need to do.
• Fix each issue, then mark the PR as "Ready for review" in the GitHub UI - but only after making sure that all the issues are fixed.
• There is no rush — take your time and work at your own pace. We appreciate your contribution and are happy to wait for updates.
• Maintainers will then proceed with a normal review.

Converting a PR to draft is not a rejection — it is an invitation to bring the PR up to the project's standards so that maintainer review time is spent productively. There is no rush — take your time and work at your own pace. We appreciate your contribution and are happy to wait for updates. If you have questions, feel free to ask on the Airflow Slack.

[bbovenzi]

We're going to need some screenshots here.