1774 extensibility v1 create an exhaustive documentation readme or dedicated section in twenty contributing doc (#16751)

As title

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packages/twenty-cli/README.md

@@ -1,89 +1,8 @@
 # Deprecated: twenty-cli
 
-This package is deprecated. Please install and use twenty-sdk instead:
+This package is deprecated. Please install and use [twenty-sdk](https://www.npmjs.com/package/twenty-sdk) instead:
 
 ```bash
 npm uninstall twenty-cli
 npm install -g twenty-sdk
 ```
-
-The command name remains the same: twenty.
-
-A command-line interface to easily scaffold, develop, and publish applications that extend Twenty CRM (now provided by twenty-sdk).
-
-## Requirements
-- yarn >= 4.9.2
-- an `apiKey`. Go to `https://twenty.com/settings/api-webhooks` to generate one
-
-## Quick example project
-
-```bash
-# Authenticate using your apiKey (CLI will prompt for your <apiKey>)
-twenty auth login
-
-# Init a new application called hello-world
-twenty app init hello-world
-
-# Go to your app
-cd hello-world
-
-# Add a serverless function to your application
-twenty app add serverlessFunction
-
-# Add a trigger to your serverless function
-twenty app add trigger
-
-# Add axios to your application
-yarn add axios
-
-# Start dev mode: automatically syncs changes to your Twenty workspace, so you can test new functions/objects instantly.
-twenty app dev
-
-# Or use one time sync (also generates SDK automatically)
-twenty app sync
-
-# List all available commands
-twenty help
-```
-
-## Application Structure
-
-Each application in this package follows the standard application structure:
-
-```
-app-name/
-├── package.json
-├── README.md
-├── serverlessFunctions  # Custom backend logic (runs on demand)
-└── ...
-```
-
-## Publish your application
-
-Applications are currently stored in twenty/packages/twenty-apps.
-
-You can share your application with all twenty users.
-
-```bash
-# pull twenty project
-git clone https://github.com/twentyhq/twenty.git
-cd twenty
-
-# create a new branch
-git checkout -b feature/my-awesome-app
-```
-
-- copy your app folder into twenty/packages/twenty-apps
-- commit your changes and open a pull request on https://github.com/twentyhq/twenty
-
-```bash
-git commit -m "Add new application"
-git push
-```
-
-Our team reviews contributions for quality, security, and reusability before merging.
-
-## Contributing
-
-- see our [Hacktoberfest 2025 notion page](https://twentycrm.notion.site/Hacktoberfest-27711d8417038037a149d4638a9cc510)
-- our [Discord](https://discord.gg/cx5n4Jzs57)

packages/twenty-cli/package.json

@@ -1,6 +1,6 @@
 {
   "name": "twenty-cli",
-  "version": "0.3.0",
+  "version": "0.3.1",
   "description": "[DEPRECATED] Use twenty-sdk instead: https://www.npmjs.com/package/twenty-sdk",
   "scripts": {
     "build": "echo 'use npx nx build'",