fix(self-inspect): declare jsonSerializable on agent-flagged RPCs (#311)

Author: JianJroh

packages/self-inspect/src/node/rpc/functions/get-devtools-plugins.ts

@@ -4,6 +4,7 @@ import { defineRpcFunction } from '@vitejs/devtools-kit'
 export const getDevtoolsPlugins = defineRpcFunction({
   name: 'devtoolskit:self-inspect:get-devtools-plugins',
   type: 'query',
+  jsonSerializable: true,
   agent: {
     description: 'List every Vite plugin involved in the current project, flagging which ones export a `devtools` hook (and whether that hook sets up any devtools surface). Read-only.',
     title: 'List devtools plugins',

packages/self-inspect/src/node/rpc/functions/get-docks.ts

@@ -3,6 +3,7 @@ import { defineRpcFunction } from '@vitejs/devtools-kit'
 export const getDocks = defineRpcFunction({
   name: 'devtoolskit:self-inspect:get-docks',
   type: 'query',
+  jsonSerializable: true,
   agent: {
     description: 'List every UI dock/panel registered on the devtools. Each entry includes id, title, icon, category, and how the dock is rendered (iframe, action, custom-render, launcher). Read-only.',
     title: 'List docks',