baseline: api+gui traffic mode + candidates picker

Snapshot before app-launcher (cgroup/mark) work; ignore binaries/backups.

selective-vpn-api/main.go

@@ -0,0 +1,9 @@
+package main
+
+import app "selective-vpn-api/app"
+
+// EN: Thin executable entrypoint that delegates runtime startup to the app package.
+// RU: Тонкая точка входа бинаря, делегирующая запуск пакету app.
+func main() {
+	app.Run()
+}