Fix #4072: 修复无法使用部分中文字体的问题

[Glavo]

No description provided.

[Copilot]

Pull Request Overview

This PR fixes issue #4072 by replacing direct JavaFX Font usage with a new FontReference abstraction to support custom Chinese fonts and updating stylesheet logic to detect default fonts by family name.

• Introduces FontReference class to store font family and optional style instead of javafx.scene.text.Font.
• Updates FontManager properties and methods to use FontReference and adjusts logging.
• Modifies getFontStyleSheet in StyleSheets to check for the default system font by its family string.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
HMCL/src/main/java/org/jackhuang/hmcl/setting/StyleSheets.java	Removed direct Font import, changed getFontStyleSheet to use FontReference and match default by family name.
HMCL/src/main/java/org/jackhuang/hmcl/setting/FontManager.java	Switched font property to FontReference, updated getters/setters, added FontReference inner class, and simplified logging.

Comments suppressed due to low confidence (2)

HMCL/src/main/java/org/jackhuang/hmcl/setting/FontManager.java:94

• [nitpick] This log may print "null" when using the default font; consider logging both the resolved family and style (or defaulting to DEFAULT_FONT.get().getFamily()) for clearer diagnostics.

        LOG.info("Font: " + fontFamily);

HMCL/src/main/java/org/jackhuang/hmcl/setting/FontManager.java:211

• Public FontReference API lacks Javadoc; consider adding class and method documentation to explain its purpose and usage.

        private final String family;