fix(gui): reopen workflow websocket when switching workflows

[seongjinyoon]

Description:

Ensure workflow executions are always attributed to the correct workflow even when reusing a computing unit across multiple workflows.

Closes #3759

Problem:

When users switch workflows without changing the computing unit, the frontend keeps the existing WebSocket session so the backend continues to use the previous wid and execution history is midfiled.

In Texera, a WebSocket connection requires wid and cuid. When we switch to a different workflow, we call registerWorkflowMetadataSubscription(). This function calls onComputingUnitChange() when wid changes, but onComputingUnitChange() only checks for changes in cuid without checking wid changes.

Solution:

Have the Angular computing-unit status service track the wid and cuid, forcing the websocket to reconnect whenever either of them change and clear the cached identifiers when the selection disappears or is terminated.
Additionally, fixed typo in core/gui/src/app/workspace/component/power-button/computing-unit-selection.component.ts

[Copilot]

Pull Request Overview

This PR fixes a bug where workflow execution history was incorrectly attributed to the previous workflow when users switched workflows without changing computing units. The websocket connection was not being reopened when only the workflow ID changed.

• Added tracking of workflow ID (wid) in addition to computing unit ID (cuid) to detect when websocket reconnection is needed
• Modified the reconnection logic to trigger when either wid or cuid changes
• Added cleanup of cached identifiers when computing units are deselected or terminated

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[seongjinyoon]

@aglinxinyuan @kunwp1

[chenlica]

@seongjinyoon Thanks for fixing the issue. Can you recommend 1-2 reviewers?

[seongjinyoon]

@seongjinyoon Thanks for fixing the issue. Can you recommend 1-2 reviewers?

I have asked @kunwp1 to review the code.

[chenlica]

I also assigned @Xiao-zhen-Liu as a reviewer.

[kunwp1]

I reviewed the PR and left a few clarification questions. If you can address them, please add comments to the code. Also, can you update the comments of the registerWorkflowMetadataSubscription and the PR description to replace onComputingUnitChange with selectComputingUnit?

[kunwp1]

It looks good to me now. Well done!

@Xiao-zhen-Liu Can you review the PR?

[Xiao-zhen-Liu]

LGTM.