Add slugify websocket command

[piitaya]

Proposed change

Adds a slugify WebSocket command that returns the slug for a given text, using the same slugify util as entity ID generation. This lets the frontend show an accurate entity ID preview when changing entity id format.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Deprecation (breaking change to happen in the future)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request:
• Link to developer documentation pull request:
• Link to frontend pull request: Use backend slugify for the entity ID format preview frontend#53394

Checklist

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[home-assistant]

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[Copilot]

Pull request overview

Adds a WebSocket command for frontend-consistent slug generation.

Changes:

• Registers config/core/slugify.
• Adds WebSocket coverage for slug generation.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
homeassistant/components/config/core.py	Implements and registers the command.
tests/components/config/test_core.py	Tests the command response.

[home-assistant]

Please take a look at the requested changes, and use the Ready for review button when you are done, thanks 👍

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

[erwindouna]

Looks good, thanks @piitaya!

[arturpragacz]

Actually should it be part of config/core?
I think it's generic enough to add it in websocket_api at the top level?

[piitaya]

I was also thinking to create a preview entity id endpoint. I'm ok with both solution.

Also, in frontend, we are generating slug for dashboard path. I guess we can re-use that endpoint for that too.

[arturpragacz]

Also, in frontend, we are generating slug for dashboard path. I guess we can re-use that endpoint for that too.

Let's make it a generic endpoint then (just slugify probably?).

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.