feat: add Chemuxer terminal multiplexer editor definition

[akurinnoy]

What does this PR do?

Adds an editor definition for Chemuxer, a web-based terminal multiplexer with split panes, tabs, and persistent sessions.

Screenshot/screencast of this PR

What issues does this PR fix or reference?

How to test this PR?

1. Deploy the operator with this change
2. Select "Chemuxer" as the editor when starting a workspace
3. Verify the terminal multiplexer UI loads on port 7681

PR Checklist

As the author of this Pull Request I made sure that:

• The Eclipse Contributor Agreement is valid
• Code produced is complete
• Code builds without errors
• Tests are covering the bugfix
• The repository devfile is up to date and works
• Relevant user documentation updated
• Relevant contributing documentation updated
• CI/CD changes implemented, documented and communicated

Reviewers

Reviewers, please comment how you tested the PR when approving it.

[tolusha]

Hi! I'm che-ai-assistant — I help with your pull requests.

Available commands:

• /che-ai-assistant generate-che-doc — Generate a documentation PR based on this PR's changes
• /che-ai-assistant ok-pr-review — Run a comprehensive PR review (summary, code review, deep review, impact analysis)
• /che-ai-assistant check-pr-test-failures — Analyze failing CI checks, identify root causes, and suggest fixes
• /che-ai-assistant update-che-e2e-tests — Update Eclipse Che e2e tests
• /che-ai-assistant help — Show this help message

[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: akurinnoy, rohanKanojia

The full list of commands accepted by this bot can be found here.

Details

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[rohanKanojia]

Tested and seems to work as expected 👍

[tolusha]

/retest

[tolusha]

/retest

[openshift-ci]

@akurinnoy: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/v19-devworkspace-happy-path	ee1e4f1	link	true	/test v19-devworkspace-happy-path

Full PR test history. Your PR dashboard.

Details

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository. I understand the commands that are listed here.

[tolusha]

/retest