[management,client] 0.75.0 release with new desktop UI (#6473)

- **Wails v3 application** (`client/ui`) with a React + TypeScript + Tailwind frontend replacing the Fyne UI: main connection view, exit-node switcher, networks/peers browser with detail panels, profile management, settings (general, network, SSH, security, troubleshooting, appearance), debug-bundle creation, and a first-run welcome flow.
- **Internationalization**: go-i18n bundle with 9 locales (en, de, es, fr, hu, it, pt, ru, zh-CN) shared between the tray and the frontend.
- **New system tray** implementation with per-platform theme-aware icons, including a native XEmbed host for Linux (`xembed_tray_linux.c`) and a Linux theme watcher.
- **Session handling**: auth session watcher (`client/internal/auth/sessionwatch`), pending login flow, session-expiration dialog and tray notifications, and `netbird login` improvements.
- **Daemon API extensions** (`daemon.proto`): status stream subscription, event stream, networks/exit-node selection endpoints, and richer full status — with probe throttling on the daemon side to protect against UI-driven request storms.
- **UI preferences store** persisted per profile, autostart management via the daemon (single source of truth in HKCU on Windows).
- **Build system**: Taskfile-based builds per platform (macOS, Linux, Windows), Docker cross-compilation images, MSIX/NSIS/nfpm/AppImage packaging, and a new `frontend-ui` CI workflow.

Co-authored-by: Zoltan Papp <zoltan.pmail@gmail.com>
Co-authored-by: Eduard Gert <kontakt@eduardgert.de>
Co-authored-by: braginini <bangvalo@gmail.com>
Co-authored-by: Pascal Fischer <32096965+pascal-fischer@users.noreply.github.com>
Co-authored-by: riccardom <riccardomanfrin@gmail.com>

client/ui/frontend/src/components/SquareIcon.tsx

@@ -0,0 +1,37 @@
+import { type ComponentType } from "react";
+import { type LucideProps } from "lucide-react";
+import { cn } from "@/lib/cn";
+
+export type SquareIconVariant = "default" | "info" | "warning" | "danger";
+
+const variantClass: Record<SquareIconVariant, string> = {
+    default: "text-white",
+    info: "text-sky-400",
+    warning: "text-netbird",
+    danger: "text-red-500",
+};
+
+type SquareIconProps = {
+    icon: ComponentType<LucideProps>;
+    iconSize?: number;
+    variant?: SquareIconVariant;
+    className?: string;
+};
+
+export const SquareIcon = ({
+    icon: Icon,
+    iconSize = 18,
+    variant = "default",
+    className,
+}: SquareIconProps) => (
+    <div
+        aria-hidden={"true"}
+        className={cn(
+            "flex h-11 w-11 items-center justify-center rounded-lg border border-nb-gray-900 bg-nb-gray-920",
+            variantClass[variant],
+            className,
+        )}
+    >
+        <Icon size={iconSize} />
+    </div>
+);