Add Hub Console with agent management and message routing

Implement Hub that auto-connects to Gateway, manages agents via REST API,
and routes WebSocket messages to agents by payload.agentId with echo responses
sent back to the original sender.

- Add Hub with GatewayClient auto-connect, agent CRUD, and message routing
- Add Console (NestJS) with REST API and static pages (management + demo client)
- Switch Gateway registration from explicit event to query-based on connect
- Remove deprecated types (RegisterPayload, metadata, SendMessagePayload)
- Add @nestjs/serve-static for serving console UI

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/console/app.module.ts

@@ -0,0 +1,48 @@
+import { Module } from "@nestjs/common";
+import { ServeStaticModule } from "@nestjs/serve-static";
+import { LoggerModule } from "nestjs-pino";
+import { join } from "node:path";
+import { fileURLToPath } from "node:url";
+import { AppController } from "./app.controller.js";
+import { Hub } from "../hub/hub.js";
+
+const __dirname = fileURLToPath(new URL(".", import.meta.url));
+const isDev = process.env["NODE_ENV"] !== "production";
+
+@Module({
+  imports: [
+    ServeStaticModule.forRoot({
+      rootPath: join(__dirname, "public"),
+      serveRoot: "/",
+      exclude: ["/api/(.*)"],
+    }),
+    LoggerModule.forRoot({
+      pinoHttp: isDev
+        ? {
+            transport: {
+              target: "pino-pretty",
+              options: {
+                colorize: true,
+                singleLine: true,
+              },
+            },
+            level: process.env["LOG_LEVEL"] ?? "debug",
+          }
+        : {
+            level: process.env["LOG_LEVEL"] ?? "info",
+          },
+    }),
+  ],
+  controllers: [AppController],
+  providers: [
+    {
+      provide: "HUB",
+      useFactory: () => {
+        const gatewayUrl =
+          process.env["GATEWAY_URL"] ?? "http://localhost:3000";
+        return new Hub(gatewayUrl);
+      },
+    },
+  ],
+})
+export class AppModule {}