feat: implement ADB wrapper and device management backend

Adds full ADB client, device manager, static DeviceInfo fetcher, and
live DeviceLiveStats poller. Exposes ListDevices, ConnectDevice,
DisconnectDevice, GetDeviceInfo, GetDeviceLiveStats as Wails-bound
methods with a 1s devices:changed event loop. Bundles ADB binary
infrastructure via //go:embed all:bin with runtime fallback chain.

backend-go/device/info.go

@@ -0,0 +1,143 @@
+package device
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"git.achmad.dev/admin/droidscope/backend/adb"
+)
+
+// FetchInfo retrieves static device information (fetched once on device select).
+func FetchInfo(ctx context.Context, client *adb.Client, deviceID string) (*DeviceInfo, error) {
+	info := &DeviceInfo{ID: deviceID}
+
+	shell := func(cmd string) string {
+		out, _ := client.Shell(ctx, deviceID, cmd)
+		return strings.TrimSpace(out)
+	}
+
+	info.Manufacturer = shell("getprop ro.product.manufacturer")
+	info.Model = shell("getprop ro.product.model")
+	info.Product = shell("getprop ro.product.name")
+	info.AndroidVersion = shell("getprop ro.build.version.release")
+	info.SDKVersion = shell("getprop ro.build.version.sdk")
+	info.SecurityPatch = shell("getprop ro.build.version.security_patch")
+	info.BuildFingerprint = shell("getprop ro.build.fingerprint")
+	info.ABI = shell("getprop ro.product.cpu.abi")
+	info.SupportedABIs = shell("getprop ro.product.cpu.abilist")
+	info.SerialNumber = shell("getprop ro.serialno")
+
+	info.ScreenResolution = shell("wm size | awk '/Physical/{print $3}'")
+	info.ScreenDensity = shell("wm density | awk '/Physical/{print $3}' | tr -d '\\n'")
+
+	info.TotalRAMMB = parseRAM(shell("cat /proc/meminfo | grep MemTotal"))
+	info.TotalStorageGB, _ = parseStorage(shell("df /data 2>/dev/null | tail -1"))
+
+	return info, nil
+}
+
+// FetchLiveStats retrieves only the fields that change at runtime.
+// Called on a 1-second poll interval.
+func FetchLiveStats(ctx context.Context, client *adb.Client, deviceID string) (*DeviceLiveStats, error) {
+	shell := func(cmd string) string {
+		out, _ := client.Shell(ctx, deviceID, cmd)
+		return strings.TrimSpace(out)
+	}
+
+	stats := &DeviceLiveStats{}
+
+	stats.AvailableRAMMB = parseRAM(shell("cat /proc/meminfo | grep MemAvailable"))
+
+	_, stats.AvailableStorageGB = parseStorage(shell("df /data 2>/dev/null | tail -1"))
+
+	batteryOut := shell("dumpsys battery")
+	stats.BatteryLevel = parseBatteryField(batteryOut, "level")
+	stats.BatteryStatus = parseBatteryStatusCode(parseBatteryField(batteryOut, "status"))
+
+	stats.ThermalStatus = parseThermalStatus(shell("dumpsys thermalservice 2>/dev/null | grep 'Current thermal status'"))
+
+	ip := shell("ip addr show wlan0 2>/dev/null | grep 'inet ' | awk '{print $2}' | cut -d/ -f1")
+	if ip == "" {
+		ip = shell("ip route get 8.8.8.8 2>/dev/null | grep src | awk '{print $7}'")
+	}
+	stats.IPAddress = ip
+
+	return stats, nil
+}
+
+func parseRAM(line string) int {
+	fields := strings.Fields(line)
+	if len(fields) < 2 {
+		return 0
+	}
+	return parseIntSafe(fields[1]) / 1024
+}
+
+func parseStorage(dfLine string) (total, available string) {
+	fields := strings.Fields(dfLine)
+	if len(fields) < 4 {
+		return "", ""
+	}
+	return formatGB(parseIntSafe(fields[1])), formatGB(parseIntSafe(fields[3]))
+}
+
+func formatGB(kb int) string {
+	if kb == 0 {
+		return ""
+	}
+	gb := float64(kb) / 1024 / 1024
+	if gb >= 1 {
+		return strings.TrimRight(strings.TrimRight(
+			strings.Replace(fmt.Sprintf("%.1f", gb), ".0", "", 1), "0"), ".") + " GB"
+	}
+	return fmt.Sprintf("%d MB", kb/1024)
+}
+
+func parseBatteryField(dumpsys, field string) int {
+	for _, line := range strings.Split(dumpsys, "\n") {
+		line = strings.TrimSpace(line)
+		if strings.HasPrefix(line, field+":") {
+			return parseIntSafe(strings.TrimSpace(strings.TrimPrefix(line, field+":")))
+		}
+	}
+	return 0
+}
+
+func parseBatteryStatusCode(code int) string {
+	switch code {
+	case 2:
+		return "charging"
+	case 3:
+		return "discharging"
+	case 4:
+		return "not charging"
+	case 5:
+		return "full"
+	default:
+		return "unknown"
+	}
+}
+
+func parseThermalStatus(line string) string {
+	parts := strings.Split(line, ":")
+	if len(parts) < 2 {
+		return "none"
+	}
+	switch parseIntSafe(strings.TrimSpace(parts[1])) {
+	case 1:
+		return "light"
+	case 2:
+		return "moderate"
+	case 3:
+		return "severe"
+	case 4:
+		return "critical"
+	case 5:
+		return "emergency"
+	case 6:
+		return "shutdown"
+	default:
+		return "none"
+	}
+}