plugins: avoid peer auto-install dependency bloat (#34017)

* plugins/install: omit peer deps during plugin npm install

* tests: assert plugin install omits peer deps

* extensions/googlechat: mark openclaw peer optional

* extensions/memory-core: mark openclaw peer optional

src/test-utils/exec-assertions.ts

@@ -11,7 +11,14 @@ export function expectSingleNpmInstallIgnoreScriptsCall(params: {
     throw new Error("expected npm install call");
   }
   const [argv, opts] = first;
-  expect(argv).toEqual(["npm", "install", "--omit=dev", "--silent", "--ignore-scripts"]);
+  expect(argv).toEqual([
+    "npm",
+    "install",
+    "--omit=dev",
+    "--omit=peer",
+    "--silent",
+    "--ignore-scripts",
+  ]);
   expect(opts?.cwd).toBe(params.expectedCwd);
 }