feat(agentswarm): optional c0mpute.com inference backend

createC0mputeModel() turns a connected c0mpute.com account (apiKey + OpenAI-
compatible base URL) into a LangChain chat model, usable as the model for
createDeepAgentRunner or the chatModel for the judge/router — so agent inference
can run on community-shared GPUs. Opt-in; default stays the hosted provider.
agentswarm performs no OAuth: the host's c0mpute connector supplies credentials
(resolveC0mputeConnector / c0mputeConnectorFromEnv normalize them). DeepAgent
runner now accepts a model instance, not just a provider string.

7 new tests (defaults, env mapping, not-connected + missing-peer errors); 34/34 pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

packages/agentswarm/src/compute.test.ts

@@ -0,0 +1,56 @@
+import { describe, expect, it } from "vitest";
+import {
+  C0MPUTE_DEFAULT_BASE_URL,
+  C0MPUTE_DEFAULT_MODEL,
+  c0mputeConnectorFromEnv,
+  createC0mputeModel,
+  resolveC0mputeConnector
+} from "./index.js";
+
+describe("resolveC0mputeConnector", () => {
+  it("applies default base URL and model", () => {
+    const resolved = resolveC0mputeConnector({ apiKey: "key" });
+    expect(resolved.baseUrl).toBe(C0MPUTE_DEFAULT_BASE_URL);
+    expect(resolved.model).toBe(C0MPUTE_DEFAULT_MODEL);
+    expect(resolved.apiKey).toBe("key");
+  });
+
+  it("keeps explicit base URL and model", () => {
+    const resolved = resolveC0mputeConnector({
+      apiKey: "key",
+      baseUrl: "https://gpu.example/v1",
+      model: "llama-3.1-70b"
+    });
+    expect(resolved.baseUrl).toBe("https://gpu.example/v1");
+    expect(resolved.model).toBe("llama-3.1-70b");
+  });
+
+  it("throws when not connected (no apiKey)", () => {
+    expect(() => resolveC0mputeConnector({ apiKey: "" })).toThrow(/connect a c0mpute\.com account/);
+  });
+});
+
+describe("c0mputeConnectorFromEnv", () => {
+  it("maps C0MPUTE_* env vars", () => {
+    const connector = c0mputeConnectorFromEnv({
+      C0MPUTE_API_KEY: "k",
+      C0MPUTE_API_URL: "https://gpu.example/v1",
+      C0MPUTE_MODEL: "m"
+    });
+    expect(connector).toEqual({ apiKey: "k", baseUrl: "https://gpu.example/v1", model: "m" });
+  });
+
+  it("yields an empty apiKey when unset (so resolve will reject)", () => {
+    expect(c0mputeConnectorFromEnv({}).apiKey).toBe("");
+  });
+});
+
+describe("createC0mputeModel", () => {
+  it("rejects when the account is not connected", async () => {
+    await expect(createC0mputeModel({ apiKey: "" })).rejects.toThrow(/apiKey/);
+  });
+
+  it("explains the optional @langchain/openai peer when it is missing", async () => {
+    await expect(createC0mputeModel({ apiKey: "key" })).rejects.toThrow(/@langchain\/openai/);
+  });
+});