Add Android node foundation with FCM push support

src/gateway/handlers/node.ts

@@ -50,10 +50,10 @@ export interface NodeStatus {
 }
 
 export interface NodePushToken {
-  provider: 'apns';
+  provider: 'apns' | 'fcm';
   token: string;
   topic?: string;
-  environment: 'sandbox' | 'production';
+  environment?: 'sandbox' | 'production';
   registeredAt: number;
 }
 
@@ -279,10 +279,10 @@ export function createNodeHandlers(deps: NodeHandlerDeps) {
       }
 
       const pushToken: NodePushToken = {
-        provider: 'apns',
+        provider: parsed.provider,
         token: parsed.token,
         topic: parsed.topic || undefined,
-        environment: parsed.environment ?? 'production',
+        environment: parsed.provider === 'apns' ? (parsed.environment ?? 'production') : undefined,
         registeredAt: Date.now(),
       };
       deps.setNodePushToken(parsed.connectionId, pushToken);