docs: add Upload-Post for publishing videos to social platforms

[mutonby]

Summary

This PR adds documentation for publishing generated videos to TikTok, YouTube Shorts, and Instagram Reels using Upload-Post.

Changes

• Added a 'Publishing Your Videos' section after Tech Stack
• Shows how to upload videos to multiple platforms with a single API call using Python

Why?

Users generate AI faceless videos but then need to manually upload them to each platform. Upload-Post provides a single API endpoint to publish to TikTok, YouTube, and Instagram simultaneously, completing the end-to-end automation.

Example

import requests

response = requests.post(
    "https://api.upload-post.com/upload",
    headers={"Authorization": "Bearer YOUR_API_KEY"},
    files={"video": open("output_video.mp4", "rb")},
    data={
        "title": "AI Generated Video",
        "platforms": "tiktok,youtube,instagram"
    }
)

This complements the existing Vadoo AI section by providing a publishing solution rather than a generation alternative.