feat(editor): add formatter status bar with smart configuration managment

[sgraband]

What it does

Introduce a new FormatterService abstraction and enhanced status bar
integration for managing document formatters across the editor.

New FormatterService (editor-formatter-service.ts):

• Define FormatterService interface for formatter management
• Provide formatter status, availability, and configuration APIs
• Support preference scope detection (User/Workspace/Folder)
• Emit events when formatters change

Monaco implementation (monaco-formatter-service.ts):

• Implement FormatterService using Monaco's language features
• Extract formatter metadata from registered providers
• Integrate with Theia's preference system for persistence

Formatter status contribution (editor-formatter-status-contribution.ts):

• Extract formatter-specific UI logic to dedicated contribution
• Handle display info for 0, 1, and multiple formatter scenarios
• Show warning/error icons for misconfigured formatters
• Provide quick pick for formatter selection with scope handling

Status bar integration (editor-language-status-service.ts):

• Add support for pinning language status items to the status bar
• Add Configure and Info buttons for formatter items in the tooltip
• Track pinned items to properly update on editor changes

Follow-ups

Breaking changes

• This PR introduces breaking changes and requires careful review. If yes, the breaking changes section in the changelog has been updated.

Attribution

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines
• User-facing text is internationalized using the nls service (for details, please see the Internationalization/Localization section in the Coding Guidelines)

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[ndoschek]

Hi @sgraband, thanks for this improvement!
Overall it looks solid to me already, but I noticed one issue and have a few suggestions, would be great if you can take another look, TIA!

1. I have one issue, when testing the formatter item in the Theia example app.
   When I try to switch the formatter, e.g. to the markdown table formatter, which is not configured as default one, I get this console error:

preference-service.ts:455 Uncaught (in promise) Error: Unable to write to Folder Settings because no resource is provided.
    at PreferenceServiceImpl.set (preference-service.ts:455:19)
    at MonacoFormatterService.setDefaultFormatter (monaco-formatter-service.ts:184:38)
    at EditorLanguageStatusService.showFormatterQuickPick (editor-language-status-service.ts:328:37)

2. I would prefer if we integrate the formatter item in the languageStatusItem ( { } ). This way the user could still pin the item if needed and we do not show it by default.

Also, could you please update the PR template, e.g. add a few test instructions, also for later reference.

PS: As discussed offline, I found a few issues with general formatting and configuring the formatting overall, but I will address this separately (GH-15959) after this PR is done.

[ndoschek]

Thanks for the update, this is great that it is embedded in the language status bar item now!

I just noticed one issue:
I think somehow folder and workspace scope got mixed up:
When i am in a single workspace, e.g. theia, I get this info for my current formatter: Configured in Folder Settings and when i am in a multi-root workspace I get Configured in Workspace Settings, while it should exactly be the other way round.

Would be great if you could have another look, TIA

[ndoschek]

Thank you @sgraband for the updates, code looks good to me and everything works now as expected. 👍

[ndoschek]

nit: we could reuse theia CSS variables here and for the margin below