Web Browser widget: add "Resize with Window" property

[gian21391]

The Web Browser widget keeps its fixed design-time size at runtime, like every other widget. For displays built around a single browser filling the screen, that's awkward — the embedded page doesn't follow the window when it is resized.

This PR adds an opt-in resize_with_window property (Behavior category, default off). When enabled, the browser grows and shrinks to fill the runtime window/tab. The default is off, so existing displays are unaffected, and the property is left out of the saved file unless it is set (older versions ignore the unknown tag).

It is intended for top-level, browser-dominant displays: the widget should be a direct child of the display root. When the browser is nested in a Group, Tabs, or embedded display the property is a no-op and logs a warning.

Checklist

• Testing:
  • The feature has automated tests
  • Tests were run
  • Added unit tests for the model property (default value, XML round-trip) and for the fit calculation; ran mvn clean install on JDK 21.
• Documentation:
  • The feature is documented
  • The documentation is up to date
  • Release notes:
    • Added an entry when adding a new feature

[sonarqubecloud]

Quality Gate passed

Issues
4 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[kasemir]

Well, the web browser widget has acknowledged limitations. Web pages with javascript may not work as expected and CPU load tends to be higher than in a "real" web browser. If your goal is to have a browser that fills the window, like a normal web browser, why don't you simply use an action button that opens the URL in a normal web browser? That way your users get the expected normal web browser behavior.

[gian21391]

The idea is to have tabs containing documentation or specific tools that are HTML based, rather than a generic browser. We have a specific use case for such a feature. Having HTML pages in an external browser is an option but not ideal at all.

[kasemir]

Sure, I can see resize_with_window being nice for images, plots, tables that are at the 'bottom' of a display so that they then extend downwards to fill the window. Also opens the door to widgets at the right growing to fill the available window widths.

[gian21391]

You are right. I did not see the value in other widgets but it could be a nice to have everywhere. Should I edit this PR to generalize this? Otherwise this could be implemented on each widget separately with distinct PRs.