[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/services/profileswitcher.go

@@ -0,0 +1,92 @@
+//go:build !android && !ios && !freebsd && !js
+
+package services
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	log "github.com/sirupsen/logrus"
+
+	"github.com/netbirdio/netbird/client/internal/profilemanager"
+)
+
+// ProfileSwitcher holds the reconnect policy shared by the tray and React
+// frontend so both flip profiles identically. The policy keys off prevStatus
+// from DaemonFeed.Get at SwitchActive entry:
+//
+//	Connected/Connecting → Switch + Down + Up; optimistic Connecting paint.
+//	NeedsLogin/LoginFailed/SessionExpired → Switch + Down; clear stale error for re-login.
+//	Idle → Switch only.
+type ProfileSwitcher struct {
+	profiles   *Profiles
+	connection *Connection
+	feed       *DaemonFeed
+}
+
+func NewProfileSwitcher(profiles *Profiles, connection *Connection, feed *DaemonFeed) *ProfileSwitcher {
+	return &ProfileSwitcher{profiles: profiles, connection: connection, feed: feed}
+}
+
+// SwitchActive switches to the named profile applying the reconnect policy.
+func (s *ProfileSwitcher) SwitchActive(ctx context.Context, p ProfileRef) error {
+	prevStatus := ""
+	if st, err := s.feed.Get(ctx); err == nil {
+		prevStatus = st.Status
+	} else {
+		log.Warnf("profileswitcher: get status: %v", err)
+	}
+
+	wasActive := strings.EqualFold(prevStatus, StatusConnected) ||
+		strings.EqualFold(prevStatus, StatusConnecting)
+	needsDown := wasActive ||
+		strings.EqualFold(prevStatus, StatusNeedsLogin) ||
+		strings.EqualFold(prevStatus, StatusLoginFailed) ||
+		strings.EqualFold(prevStatus, StatusSessionExpired)
+
+	log.Infof("profileswitcher: switch profile=%q prevStatus=%q wasActive=%v needsDown=%v",
+		p.ProfileName, prevStatus, wasActive, needsDown)
+
+	// Optimistic Connecting paint only when wasActive: those prevStatuses emit
+	// stale Connected + transient Idle pushes during Down that must be
+	// suppressed until Up resumes the stream (see DaemonFeed suppression table).
+	if wasActive {
+		s.feed.BeginProfileSwitch()
+	}
+
+	resolvedID, err := s.profiles.Switch(ctx, p)
+	if err != nil {
+		return fmt.Errorf("switch profile %q: %w", p.ProfileName, err)
+	}
+
+	// Mirror into the user-side ProfileManager state: the CLI's `netbird up`
+	// reads this file and sends the ID back in the Up RPC, so if it diverges
+	// the daemon reverts the UI switch on the next CLI `up`. Best-effort — the
+	// daemon is authoritative; a failure only leaves the CLI's view stale.
+	// Use the daemon-resolved ID rather than the handle we sent, since the
+	// on-disk state is keyed by ID, not display name.
+	if err := profilemanager.NewProfileManager().SwitchProfile(profilemanager.ID(resolvedID)); err != nil {
+		log.Warnf("profileswitcher: mirror to user-side ProfileManager failed: %v", err)
+	}
+
+	if needsDown {
+		if err := s.connection.Down(ctx); err != nil {
+			log.Errorf("profileswitcher: Down: %v", err)
+		}
+	}
+
+	if wasActive {
+		if err := s.connection.Up(ctx, UpParams(p)); err != nil {
+			return fmt.Errorf("reconnect %q: %w", p.ProfileName, err)
+		}
+	}
+
+	// The daemon emits no profile event, so fan out ourselves or the React
+	// ProfileContext stays on the old profile after a tray-initiated switch.
+	if s.feed != nil && s.feed.emitter != nil {
+		s.feed.emitter.Emit(EventProfileChanged, p)
+	}
+
+	return nil
+}