Redesign UI like Driver Navigator + fix CMD window

UI changes:
- Top title bar with logo, app name, and system status LED
- Toolbar with 4 icon tabs: Scan, Drivers, Download, System
- Scan page with computer SVG illustration, stats, and big SCAN NOW button
- Step indicator bar: Scan Devices > Review Drivers > Install Updates
- Driver list with per-row progress bars, Download + Install buttons
- "Update All Drivers" CTA bar at bottom when outdated drivers found
- Windows Update tab with pending/installed sections
- System Info tab with resource bars
- Footer with About/Help buttons

Backend fixes:
- Add cmdutil.HiddenCommand() using CREATE_NO_WINDOW (0x08000000)
- All PowerShell subprocesses now run without visible console window
- Build with -ldflags "-H windowsgui" to hide main CMD window

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

internal/sysinfo/sysinfo.go

@@ -2,11 +2,12 @@ package sysinfo
 
 import (
 	"fmt"
-	"os/exec"
 	"runtime"
 	"strings"
 	"syscall"
 	"unsafe"
+
+	"github.com/mumur/driver-booster/internal/cmdutil"
 )
 
 var (
@@ -117,7 +118,7 @@ func getComputerName() string {
 }
 
 func getCPUName() string {
-	out, err := exec.Command("powershell", "-NoProfile", "-Command",
+	out, err := cmdutil.HiddenCommand("powershell", "-NoProfile", "-Command",
 		"(Get-CimInstance Win32_Processor).Name").Output()
 	if err != nil {
 		return "Unknown CPU"
@@ -126,7 +127,7 @@ func getCPUName() string {
 }
 
 func getWindowsProductName() string {
-	out, err := exec.Command("powershell", "-NoProfile", "-Command",
+	out, err := cmdutil.HiddenCommand("powershell", "-NoProfile", "-Command",
 		"(Get-CimInstance Win32_OperatingSystem).Caption").Output()
 	if err != nil {
 		return "Windows"