Document build steps with @nextcloud/excalidraw

• Document development steps
• Document release steps

My attempt locally:

cd ~/repos/nextcloud/excalidraw

cd packages/excalidraw
yarn && yarn build:esm
yarn link
cd ../../

cd packages/elements
yarn
yarn link @nextcloud/excalidraw
yarn build:esm

cd ~/repos/nextcloud/server/apps-extra/whiteboard
npm ci
npm link ~/repos/nextcloud/excalidraw/packages/{common,math,excalidraw,element}

--- a/vite.config.ts
+++ b/vite.config.ts
@@ -6,6 +6,7 @@ import react from '@vitejs/plugin-react'
 import { defineConfig, normalizePath } from 'vite'
 import { join, resolve } from 'path'
 import { viteStaticCopy } from 'vite-plugin-static-copy'
+import { nodePolyfills } from 'vite-plugin-node-polyfills'

 const EXCALIDRAW_FONTS_DIR = normalizePath(resolve('node_modules/@nextcloud/excalidraw/dist/prod/fonts'))

@@ -62,6 +63,9 @@ const AppConfig = createAppConfig({
                        jsxInject: 'import React from \'react\'',
                },
                plugins: [
+                       nodePolyfills({
+                               include: ['process', 'buffer', 'global'],
+                       }),
                        react({
                                jsxRuntime: 'classic',
                        }),

Start by reviewing the development commands for packages/excalidraw, packages/elements, and the whiteboard app, then inspect vite.config.ts and the existing documentation. Verify the documented development and release steps against the repository's current scripts. Done means both checklists are complete and a newcomer can follow them without relying on local linking assumptions.