Share Extension SHARE EXTENSION: SETUP: Requires separate extension target (kind: "share" in plan extensions array). The extension receives shared content (URLs, text, images) from other apps via the share sheet. PRINCIPAL CLASS (in extension target): class ShareViewController: SLComposeServiceViewController { override func isContentValid() - Bool { return contentText.count 0 // Validate before enabling Post button } override func didSelectPost() { // Access shared items guard let item = extensionContext?.inputItems.first as? NSExtensionItem, let provider = item.attachments?.first else { exte…