POC: vscode-free @cline/sdk driver with unit test (Feature #2)

fetchSdkSummary() dynamic-imports the ESM-only SDK and returns its build
version + builtin tool catalog (pure, key-free). Kept vscode-free so it is
unit-testable in Node; test asserts a semver version and the read_files tool.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

test/cline.test.ts

@@ -0,0 +1,15 @@
+import { describe, it, expect } from "vitest";
+import { fetchSdkSummary } from "../src/cline";
+
+describe("fetchSdkSummary", () => {
+  it("loads @cline/sdk and returns its version and builtin tool catalog", async () => {
+    const summary = await fetchSdkSummary();
+    expect(summary.version).toMatch(/^\d+\.\d+\.\d+/);
+    expect(summary.tools.length).toBeGreaterThan(0);
+    expect(summary.tools.map((t) => t.id)).toContain("read_files");
+    for (const tool of summary.tools) {
+      expect(typeof tool.id).toBe("string");
+      expect(typeof tool.description).toBe("string");
+    }
+  });
+});