chore: import upstream snapshot with attribution

tests/unit/opencode-strip-client-metadata-1442.test.ts

@@ -0,0 +1,52 @@
+import { describe, it } from "node:test";
+import assert from "node:assert/strict";
+
+const { OpencodeExecutor } = await import("../../open-sse/executors/opencode.ts");
+
+/**
+ * Regression test for upstream decolua/9router#1442:
+ *
+ * OpenCode upstreams (e.g. kimi-k2.6 via opencode-go) reject the
+ * `client_metadata` passthrough field (an OpenAI-Codex/Claude-CLI artifact)
+ * with 400 "Extra inputs are not permitted, field: 'client_metadata'".
+ * DefaultExecutor strips it only for cerebras/mistral, and OpencodeExecutor
+ * extends BaseExecutor directly, so nothing removed it on the opencode path.
+ * OpencodeExecutor.transformRequest must strip it.
+ */
+describe("OpencodeExecutor — strips client_metadata (#1442)", () => {
+  const executor = new OpencodeExecutor("opencode-go");
+  const CREDENTIALS = { apiKey: "k" } as Record<string, unknown>;
+
+  function body() {
+    return {
+      model: "oc/kimi-k2.6",
+      stream: true,
+      client_metadata: { user_id: "abc" },
+      messages: [{ role: "user", content: "hi" }],
+    };
+  }
+
+  it("removes client_metadata from the forwarded body", () => {
+    const out = executor.transformRequest("oc/kimi-k2.6", body(), true, CREDENTIALS) as Record<
+      string,
+      unknown
+    >;
+    assert.equal(
+      Object.prototype.hasOwnProperty.call(out, "client_metadata"),
+      false,
+      "opencode forward body must not carry client_metadata"
+    );
+    assert.ok(Array.isArray(out.messages), "messages preserved");
+  });
+
+  it("is a no-op when client_metadata is absent", () => {
+    const b = body();
+    delete (b as Record<string, unknown>).client_metadata;
+    const out = executor.transformRequest("oc/kimi-k2.6", b, true, CREDENTIALS) as Record<
+      string,
+      unknown
+    >;
+    assert.equal("client_metadata" in out, false);
+    assert.ok(Array.isArray(out.messages));
+  });
+});