refactor(plugin-sdk): consolidate tool result helpers (#99740)

* refactor(plugin-sdk): consolidate tool result helpers

* docs(plugin-sdk): tighten tool result guidance

* refactor(feishu): use tool results directly

src/plugin-sdk/tool-results.test.ts

@@ -0,0 +1,31 @@
+import { describe, expect, expectTypeOf, it, vi } from "vitest";
+
+vi.mock("../agents/tools/common.js", () => {
+  throw new Error("tool-results must not load the broad agent tool helpers");
+});
+
+import { jsonResult, textResult, type AgentToolResult } from "./tool-results.js";
+
+describe("tool result helpers", () => {
+  it("preserves typed JSON details", () => {
+    const payload = { ok: true, messageId: "msg-1" };
+    const result = jsonResult(payload);
+
+    expectTypeOf(result).toEqualTypeOf<AgentToolResult<typeof payload>>();
+    expect(result).toEqual({
+      content: [{ type: "text", text: JSON.stringify(payload, null, 2) }],
+      details: payload,
+    });
+  });
+
+  it("keeps model text separate from typed details", () => {
+    const details = { ok: true, messageId: "msg-1" };
+    const result = textResult("Message sent.", details);
+
+    expectTypeOf(result).toEqualTypeOf<AgentToolResult<typeof details>>();
+    expect(result).toEqual({
+      content: [{ type: "text", text: "Message sent." }],
+      details,
+    });
+  });
+});

src/plugin-sdk/tool-results.ts

@@ -0,0 +1,2 @@
+export type { AgentToolResult } from "../agents/runtime/index.js";
+export { jsonResult, textResult } from "../agents/tools/tool-results.js";