feat: make playwright optional

tests/install-local.test.ts

@@ -199,6 +199,18 @@ test("reinstall replaces bundles while preserving existing settings and plugin o
     expect(await readFile(join(setup.installed, "index.js"), "utf8")).toContain('return "second"');
 });
 
+test("enables Playwright only when requested", async () => {
+    const setup = await fixture();
+    const result = await run(
+        ["bash", join(setup.checkout, "install-local.sh"), "--playwright"],
+        setup.cwd,
+        setup.env,
+    );
+    expect(result, result.stderr).toMatchObject({ exitCode: 0 });
+    const installed = JSON.parse(await readFile(join(setup.config, "opencode.json"), "utf8"));
+    expect(installed.plugins.at(-1).options.playwright).toBe(true);
+});
+
 for (const mode of ["dependency", "build", "validation", "config"] as const) {
     test(`${mode} failure leaves the previous installation and configuration untouched`, async () => {
         const invalidConfig = mode === "config" ? { plugins: "not-an-array" } : undefined;