Add jdk-jsobject so javafx.web (WebView) builds on JDK 26

[gian21391]

MergedLogEntryDisplayController uses netscape.javascript.JSObject to bridge the
Olog WebView to Java. That class was provided by the JDK's jdk.jsobject module,
which is removed in JDK 26, so javafx.web no longer compiles or resolves there.

Since JavaFX 24 that module is shipped with JavaFX as the upgradable
org.openjfx:jdk-jsobject artifact; this adds it to the classpath. It is versioned
independently of openjfx.version because the standalone artifact only exists from
25 onwards. On JDK 25 and earlier the platform module still takes precedence, so the
dependency is inert; on JDK 26 it supplies netscape.javascript.

Together with #3851 (which replaces the removed Thread.stop()), this clears the
second and final compile blocker, so the project builds and runs on JDK 26.

Checklist

• Testing:
  • The feature has automated tests
  • Tests were run
  • If not, explain how you tested your changes
    • Built the full reactor and ran the test suite on both the JDK 21 target
      and JDK 26 (2332 tests, 0 failures on each). On JDK 21 the JDK's own
      jdk.jsobject still takes precedence (behavior unchanged); on JDK 26
      netscape.javascript resolves from the bundled artifact and the embedded
      WebView renders a page.
• Documentation:
  • The feature is documented
  • The documentation is up to date
  • Release notes:
    • Added an entry if the change is breaking or significant
    • Added an entry when adding a new feature

[sonarqubecloud]

Quality Gate passed

Issues
0 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

[gian21391]

Note: this overlaps with #3839 (JDK 25 bump) — that PR moves openjfx.version to 25, which already pulls in jdk-jsobject transitively. This PR adds it explicitly so it's guaranteed on the classpath for JDK 26.