[client/ui] Introduce localisation (i18n + preferences) feature packages

Adds a tray + React translation pipeline driven by a single JSON locale
tree (frontend/src/i18n/locales) embedded into the Go binary. The tray
re-renders on language switch via a Localizer that subscribes to the
preferences store.

Layout:
- client/ui/i18n: Bundle, LanguageCode, Language, errors, embedded-FS
  loader. Pure domain, no Wails/daemon deps.
- client/ui/preferences: Store + UIPreferences for user-scope UI state,
  persisted under os.UserConfigDir()/netbird/ui-preferences.json with
  atomic writes and a subscribe/broadcast channel.
- client/ui/services: thin Wails-binding facades (services.I18n,
  services.Preferences) so React sees ctx-first signatures.
- client/ui/localizer.go: tray bridge that owns the active language,
  exposes T()/StatusLabel() and re-paints the menu on prefs change.
- tray.go: every user-facing const replaced by translation keys via
  t.loc.T(...); menu rebuild + state replay on language switch.
- main.go: //go:embed all:frontend/src/i18n/locales, wires Bundle ->
  Store -> Localizer -> Wails facades in order.

Frontend API exposed via Wails bindings: I18n.Languages, I18n.Bundle,
Preferences.Get, Preferences.SetLanguage, plus the
netbird:preferences:changed event.

Includes regenerated Wails TS bindings (peers/profileswitcher/etc.
re-emitted as part of the build) and en/hu seed bundles.

client/ui/frontend/src/i18n/locales/_index.json

@@ -0,0 +1,6 @@
+{
+    "languages": [
+        {"code": "en", "displayName": "English", "englishName": "English"},
+        {"code": "hu", "displayName": "Magyar", "englishName": "Hungarian"}
+    ]
+}

client/ui/frontend/src/i18n/locales/en/common.json

@@ -0,0 +1,34 @@
+{
+    "tray.tooltip": "NetBird",
+    "tray.status.disconnected": "Disconnected",
+    "tray.status.daemonUnavailable": "Not running",
+    "tray.status.error": "Error",
+
+    "tray.menu.open": "Open NetBird",
+    "tray.menu.connect": "Connect",
+    "tray.menu.disconnect": "Disconnect",
+    "tray.menu.exitNode": "Exit Node",
+    "tray.menu.networks": "Resources",
+    "tray.menu.profiles": "Profiles",
+    "tray.menu.settings": "Settings",
+    "tray.menu.debugBundle": "Create Debug Bundle",
+    "tray.menu.about": "About",
+    "tray.menu.github": "GitHub",
+    "tray.menu.documentation": "Documentation",
+    "tray.menu.downloadLatest": "Download latest version",
+    "tray.menu.installVersion": "Install version {version}",
+    "tray.menu.guiVersion": "GUI: {version}",
+    "tray.menu.daemonVersion": "Daemon: {version}",
+    "tray.menu.versionUnknown": "—",
+    "tray.menu.quit": "Quit",
+
+    "notify.update.title": "NetBird update available",
+    "notify.update.body": "NetBird {version} is available.",
+    "notify.update.enforcedSuffix": " Your administrator requires this update.",
+    "notify.error.title": "Error",
+    "notify.error.connect": "Failed to connect",
+    "notify.error.disconnect": "Failed to disconnect",
+    "notify.error.switchProfile": "Failed to switch to {profile}",
+    "notify.sessionExpired.title": "NetBird session expired",
+    "notify.sessionExpired.body": "Your NetBird session has expired. Please log in again."
+}

client/ui/frontend/src/i18n/locales/hu/common.json

@@ -0,0 +1,34 @@
+{
+    "tray.tooltip": "NetBird",
+    "tray.status.disconnected": "Lekapcsolva",
+    "tray.status.daemonUnavailable": "Nem fut",
+    "tray.status.error": "Hiba",
+
+    "tray.menu.open": "NetBird megnyitása",
+    "tray.menu.connect": "Csatlakozás",
+    "tray.menu.disconnect": "Bontás",
+    "tray.menu.exitNode": "Kilépő csomópont",
+    "tray.menu.networks": "Erőforrások",
+    "tray.menu.profiles": "Profilok",
+    "tray.menu.settings": "Beállítások",
+    "tray.menu.debugBundle": "Hibakeresési csomag készítése",
+    "tray.menu.about": "Névjegy",
+    "tray.menu.github": "GitHub",
+    "tray.menu.documentation": "Dokumentáció",
+    "tray.menu.downloadLatest": "Legfrissebb verzió letöltése",
+    "tray.menu.installVersion": "{version} verzió telepítése",
+    "tray.menu.guiVersion": "Felület: {version}",
+    "tray.menu.daemonVersion": "Daemon: {version}",
+    "tray.menu.versionUnknown": "—",
+    "tray.menu.quit": "Kilépés",
+
+    "notify.update.title": "NetBird frissítés elérhető",
+    "notify.update.body": "Elérhető a NetBird {version}.",
+    "notify.update.enforcedSuffix": " A rendszergazda kötelezővé tette ezt a frissítést.",
+    "notify.error.title": "Hiba",
+    "notify.error.connect": "Csatlakozás sikertelen",
+    "notify.error.disconnect": "Bontás sikertelen",
+    "notify.error.switchProfile": "Átváltás sikertelen erre: {profile}",
+    "notify.sessionExpired.title": "NetBird munkamenet lejárt",
+    "notify.sessionExpired.body": "A NetBird munkamenet lejárt. Kérjük, jelentkezzen be újra."
+}