feat(acp): add experimental ACP support

Co-authored-by: Jonathan Taylor <visionik@pobox.com>

src/acp/session-mapper.test.ts

@@ -0,0 +1,57 @@
+import { describe, expect, it, vi } from "vitest";
+
+import type { GatewayClient } from "../gateway/client.js";
+import { parseSessionMeta, resolveSessionKey } from "./session-mapper.js";
+
+function createGateway(resolveLabelKey = "agent:main:label"): {
+  gateway: GatewayClient;
+  request: ReturnType<typeof vi.fn>;
+} {
+  const request = vi.fn(async (method: string, params: Record<string, unknown>) => {
+    if (method === "sessions.resolve" && "label" in params) {
+      return { ok: true, key: resolveLabelKey };
+    }
+    if (method === "sessions.resolve" && "key" in params) {
+      return { ok: true, key: params.key as string };
+    }
+    return { ok: true };
+  });
+
+  return {
+    gateway: { request } as unknown as GatewayClient,
+    request,
+  };
+}
+
+describe("acp session mapper", () => {
+  it("prefers explicit sessionLabel over sessionKey", async () => {
+    const { gateway, request } = createGateway();
+    const meta = parseSessionMeta({ sessionLabel: "support", sessionKey: "agent:main:main" });
+
+    const key = await resolveSessionKey({
+      meta,
+      fallbackKey: "acp:fallback",
+      gateway,
+      opts: {},
+    });
+
+    expect(key).toBe("agent:main:label");
+    expect(request).toHaveBeenCalledTimes(1);
+    expect(request).toHaveBeenCalledWith("sessions.resolve", { label: "support" });
+  });
+
+  it("lets meta sessionKey override default label", async () => {
+    const { gateway, request } = createGateway();
+    const meta = parseSessionMeta({ sessionKey: "agent:main:override" });
+
+    const key = await resolveSessionKey({
+      meta,
+      fallbackKey: "acp:fallback",
+      gateway,
+      opts: { defaultSessionLabel: "default-label" },
+    });
+
+    expect(key).toBe("agent:main:override");
+    expect(request).not.toHaveBeenCalled();
+  });
+});