refactor: extract shared sandbox and gateway plumbing

src/gateway/http-utils.request-context.test.ts

@@ -0,0 +1,45 @@
+import type { IncomingMessage } from "node:http";
+import { describe, expect, it } from "vitest";
+import { resolveGatewayRequestContext } from "./http-utils.js";
+
+function createReq(headers: Record<string, string> = {}): IncomingMessage {
+  return { headers } as IncomingMessage;
+}
+
+describe("resolveGatewayRequestContext", () => {
+  it("uses normalized x-openclaw-message-channel when enabled", () => {
+    const result = resolveGatewayRequestContext({
+      req: createReq({ "x-openclaw-message-channel": " Custom-Channel " }),
+      model: "openclaw",
+      sessionPrefix: "openai",
+      defaultMessageChannel: "webchat",
+      useMessageChannelHeader: true,
+    });
+
+    expect(result.messageChannel).toBe("custom-channel");
+  });
+
+  it("uses default messageChannel when header support is disabled", () => {
+    const result = resolveGatewayRequestContext({
+      req: createReq({ "x-openclaw-message-channel": "custom-channel" }),
+      model: "openclaw",
+      sessionPrefix: "openresponses",
+      defaultMessageChannel: "webchat",
+      useMessageChannelHeader: false,
+    });
+
+    expect(result.messageChannel).toBe("webchat");
+  });
+
+  it("includes session prefix and user in generated session key", () => {
+    const result = resolveGatewayRequestContext({
+      req: createReq(),
+      model: "openclaw",
+      user: "alice",
+      sessionPrefix: "openresponses",
+      defaultMessageChannel: "webchat",
+    });
+
+    expect(result.sessionKey).toContain("openresponses-user:alice");
+  });
+});