[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/internal/profilemanager/state.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"os"
 	"path/filepath"
 
 	"github.com/netbirdio/netbird/util"
@@ -71,3 +72,22 @@ func (pm *ProfileManager) SetActiveProfileState(state *ProfileState) error {
 
 	return nil
 }
+
+// RemoveProfileState deletes the per-profile state file (which holds the
+// account email used for the SSO login hint and the UI display). Called after
+// a successful logout so a logged-out profile no longer shows a stale account
+// email. The state file only stores the email, so deleting it is equivalent to
+// clearing it; the next SSO login recreates it. A missing file is not an error.
+func (pm *ProfileManager) RemoveProfileState(profileName string) error {
+	configDir, err := getConfigDir()
+	if err != nil {
+		return fmt.Errorf("get config directory: %w", err)
+	}
+
+	stateFile := filepath.Join(configDir, profileName+".state.json")
+	if err := os.Remove(stateFile); err != nil && !os.IsNotExist(err) {
+		return fmt.Errorf("remove profile state: %w", err)
+	}
+
+	return nil
+}