platform: modularize api/gui, add docs-tests-web foundation, and refresh root config

selective-vpn-gui/main_window/singbox/links_mixin.py

@@ -0,0 +1,16 @@
+from __future__ import annotations
+
+from main_window.singbox.links_actions_mixin import SingBoxLinksActionsMixin
+from main_window.singbox.links_helpers_mixin import SingBoxLinksHelpersMixin
+from main_window.singbox.links_parsers_mixin import SingBoxLinksParsersMixin
+
+
+class SingBoxLinksMixin(
+    SingBoxLinksActionsMixin,
+    SingBoxLinksParsersMixin,
+    SingBoxLinksHelpersMixin,
+):
+    """Facade mixin for SingBox link import/create workflow."""
+
+
+__all__ = ["SingBoxLinksMixin"]