fix: include codex plugin manifest in npm package

package.json

@@ -40,6 +40,7 @@
     "packages/shared-skills/skills",
     "packages/omo-codex/marketplace.json",
     "packages/omo-codex/plugin",
+    "packages/omo-codex/plugin/.codex-plugin",
     "packages/omo-codex/scripts"
   ],
   "exports": {

src/cli/install-codex/codex-package-manifest.test.ts

@@ -0,0 +1,17 @@
+/// <reference types="bun-types" />
+
+import { describe, expect, test } from "bun:test"
+import packageJson from "../../../package.json" with { type: "json" }
+
+describe("Codex package manifest", () => {
+  test("includes the aggregate Codex plugin manifest in npm packages", () => {
+    // given
+    const files = packageJson.files
+
+    // when
+    const includesCodexManifestDirectory = files.includes("packages/omo-codex/plugin/.codex-plugin")
+
+    // then
+    expect(includesCodexManifestDirectory).toBe(true)
+  })
+})