feat(core): add window zoom status bar item and fix secondary window zoom

[ndoschek]

What it does

Resolves GH-17163
Resolves GH-11843

Zoom status bar item:

• Adds a prominent status bar item with a zoom-in/zoom-out icon when the window zoom level is not at default
• Provides an interactive tooltip with zoom controls (+/-, reset, open preferences)
• Extracts window zoom preference keys as reusable constants
• Updates the zoom level preference description with accurate localization and step size (~10% per 0.5 step)
• Extracts Chromium's zoom base factor (1.2) as a named constant (ZoomLevel.ZOOM_BASE)

Secondary window zoom fix:

• Routes setZoomLevel IPC via windowName to target specific secondary windows
• Applies the current zoom level to newly created secondary windows

How to test

1. Start the Electron example app
2. Use View > Zoom In / View > Zoom Out (or keybindings) to change the zoom level
3. Verify a status bar item appears on the right showing a zoom-in or zoom-out icon
4. Hover over the status bar item and verify the tooltip shows zoom controls (+/-, reset, settings gear) with keybindings
5. Use the tooltip buttons to zoom in, zoom out, reset, or open preferences
6. Verify the status bar item disappears when zoom is reset to default (0)
7. Open a secondary window (e.g., extract a widget) and verify it inherits the current zoom level
8. Change the zoom level and verify secondary windows update accordingly

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

[sgraband]

Thanks for the improvement @ndoschek. Works great! I have a few inline comments and a general remark:

• imho the dialog should stay open if the + and - buttons are pressed, this way i could increase the zoom multiple times, coudl you check this?
• Also is there a reason, why the background of this item is different from the other statusbar items (light theme)? (EDIT: i believe this is fixed with #17161, right?)

[sgraband]

Should we dispose this?

[ndoschek]

ElectronSecondaryWindowService is bound as a singleton that lives for the entire application lifecycle, so the preference listener doesn't need explicit disposal - it should remain active as long as the application is running.

[ndoschek]

Thanks for the review @sgraband!

Ad 1: I don't think keeping the tooltip open on +/- would actually improve the UX here. Since each zoom step changes the page's zoom level, the status bar item itself shifts position, which means the tooltip would also need to reposition. The user would have to move their mouse to the new location anyway, at which point the tooltip reappears with the updated zoom level. So the current behavior of closing and re-showing on hover feels natural for this case IMO.

Ad 2: The different background is intentional - the item uses the prominent status bar colors, (statusBarItem.prominentBackground / statusBarItem.prominentForeground) to visually highlight that the zoom level is not at its default value. (see also #16877 for details, the workspace trust uses a prominent background as well).

[sgraband]

Thanks for the explanation! LGTM 👍