Publish content to social media platforms.
MEDIA RULES:
• mediaUrl must be a public HTTPS URL — NOT a local file path.
• If the user shares an image/video in chat, call create_upload_session FIRST to get a browser upload link, then use the returned URL here.
• Text-only works on: LinkedIn, Threads, X, Facebook.
• Image required: Instagram, Pinterest.
• TikTok supports one video or 1-35 Photo Mode images.
• Video required: YouTube.
Call validate_content to check before publishing.
Connector