Add Android client support and unify cross-platform builds

internal/client/tunnel/options.go

@@ -0,0 +1,41 @@
+package tunnel
+
+import "time"
+
+// PlatformFeatures controls which platform-specific capabilities the client may use.
+type PlatformFeatures struct {
+	AllowSelfUpdate   bool
+	AllowScreenshot   bool
+	AllowShellExecute bool
+	AllowSystemStats  bool
+}
+
+// ClientOptions controls optional client runtime settings.
+type ClientOptions struct {
+	DataDir           string
+	ClientID          string
+	ClientName        string
+	Features          *PlatformFeatures
+	ReconnectDelay    time.Duration
+	ReconnectMaxDelay time.Duration
+}
+
+// DefaultPlatformFeatures enables the desktop feature set.
+func DefaultPlatformFeatures() PlatformFeatures {
+	return PlatformFeatures{
+		AllowSelfUpdate:   true,
+		AllowScreenshot:   true,
+		AllowShellExecute: true,
+		AllowSystemStats:  true,
+	}
+}
+
+// MobilePlatformFeatures disables capabilities that are unsuitable for a mobile sandbox.
+func MobilePlatformFeatures() PlatformFeatures {
+	return PlatformFeatures{
+		AllowSelfUpdate:   false,
+		AllowScreenshot:   false,
+		AllowShellExecute: false,
+		AllowSystemStats:  true,
+	}
+}