feat: ship verified platform upgrades with channel bundle releases

Package production dependencies per architecture for online and offline upgrades.
Validate dependencies and isolated backend startup before readiness, repair once
when permitted, and preserve service/data through failed preparation or rollback.

Publish release bundles with master images and expose an opt-in develop build
sharing the development index across Alpine and Debian images.

back/services/grpc.ts

@@ -50,13 +50,13 @@ export class GrpcServerService {
       for (const host of hostsToTry) {
         try {
           const address = this.formatGrpcAddress(host, grpcPort);
-          await bindAsync(address, credentials);
+          const boundPort = await bindAsync(address, credentials);
           Logger.debug(`[boot] gRPC service started successfully on ${address}`);
           metricsService.record('grpc_service_start', 1, {
             port: grpcPort.toString(),
             host
           });
-          return grpcPort;
+          return boundPort;
         } catch (err) {
           lastError = err as Error;
           Logger.warn(`Failed to bind gRPC on ${host}:${grpcPort}, trying next...`, err);