Add Appwrite Functionality for LangX Copilot with POST Request Support

[xuelink]

This pull request adds Appwrite functionality to LangX Copilot, allowing it to handle POST requests and expanding its integration capabilities beyond Discord. The changes include updating the setup_env.js file to write system instructions and chat history to the .env file, updating the package.json file to include a prebuild script, updating the file paths for system instructions and chat history, and adding a new file, instructions.js, to handle Appwrite interactions. This feature will enhance the usability and versatility of LangX Copilot, enabling developers to leverage it in different environments. Fixes #6

[langx-copilot]

LangX 650750d21e4a6a589be3

Function	ID	Status	Action
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Project name: LangX
Project ID: 650750d21e4a6a589be3

Function	ID	Status	Action
copilot	6655d231002b1c00aa3b	Waiting to build	View Logs

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