DragView: DSH File Drag-and-Drop and Secure Preview Plugin

The DragView plugin listens for drag-and-drop events to inject local files directly into the DeepSeek Harness chat interface, generating Codex-style cards. It supports PDF, audio/video, and text previews, as well as opening files via the system, and provides two modes: resolve (file path resolution) and copy (file byte copying). Security mechanisms such as opaque IDs, path validation, and CSP ensure secure file access. After users drag files in, they can view the card in the input box and preview or open it as needed; when sending, the file reference path is appended.