fix(linux): honor desktop display scaling

[veryCrunchy]

A Linux user reports that the desktop app ignores Wayland display scaling and requires desktop magnification. The report describes a pre-redesign August 2026 nightly; its older diagnostic archive is unavailable, so this has not yet been reproduced on the current app.

Acceptance criteria:

• Verify fractional and integer display scaling on supported Linux desktops, including mixed-scale monitors where available.
• Honor OS scaling without overriding explicit user JVM scale settings.
• Keep text, pointer hit areas, window sizing, and image previews consistent.
• Document tested runtime/display combinations and distinguish XWayland from native Wayland behavior.

Retest current packaged builds before choosing a runtime or application change.