[FLINK-40118][runtime-web] Use REST endpoint field instead of removed host field

[spuru9]

What is the purpose of the change

The job Timeline tab's SubTask view and the SubTask Accumulators table both render N - undefined instead of the TaskManager location for each subtask.

Brief change log

• FLINK-36355 removed the deprecated host field from the REST API's subtask-level responses (SubtasksTimesInfo, SubtaskExecutionAttemptDetailsInfo, SubtasksAllAccumulatorsInfo), keeping only endpoint. That PR ([FLINK-36355][runtime] Remove deprecated REST APIs #25436) touched only backend Java classes; the web-dashboard frontend was never updated to match, so task.host has read undefined since Flink 2.0.
• Update JobSubTaskTime (job-timeline.ts) and SubTaskAccumulators (job-accumulators.ts) to declare endpoint instead of host.
• Update the two consumers — job-timeline.component.ts (SubTask TimeLine chart labels) and job-overview-drawer-accumulators.component.html (SubTask Accumulators table) — to read task.endpoint / subTaskAccumulator.endpoint.

Verifying this change

• npm run lint and npm run build pass.
• Verified against a real running JobManager (local standalone cluster + StateMachineExample): before the fix, the Timeline tab's SubTask view showed 0 - undefined; after the fix, it shows 0 - localhost:<port>.

Before:

After:

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): no
• The public API, i.e., is any changed class annotated with @Public(Evolving): no
• The serializers: no
• The runtime per-record code paths (performance sensitive): no
• Anything that affects deployment or recovery: no
• The S3 file system connector: no

Documentation

• Does this pull request introduce a new feature? no (bug fix)
• If yes, how is the feature documented? not applicable

AI Usage Disclosure

• Claude Code

[flinkbot]

CI report:

• ca287a4 Azure: SUCCESS

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[spuru9]

@RocMarshal @och5351 Can you help me review/merge this minor fix.

[RocMarshal]

Thanks for the patch!

@spuru9

Is the patch a breaking change of REST-API ?

[spuru9]

Is the patch a breaking change of REST-API ?

This PR only touches frontend TypeScript/HTML files (interfaces + two components) — no Java/REST API code at all. It is in response to the breaking change long back in FLINK-36355 / #25436, merged 2024-10-01, well before Flink 2.0 shipped.

[RocMarshal]

Thanks @spuru9 for the confirmation.

Attributed to the latest version of 2.x is 2.3, which means more than 2 editions in distance to 2.0.
I'll merge the patch if there're no more comments at least three days.

[spuru9]

It would need any backport? Considering it had been there for a long time, should be fine.

[RocMarshal]

Nice idea.
And May we do it after merging?

[spuru9]

And May we do it after merging?

Yes sure.

[spuru9]

Can we merge this now @RocMarshal @davidradl ?