dsh-drop-in: Drag and drop or paste files in the DSH Web input box to send with the message

dsh-drop-in is a plugin designed specifically for the DSH Web interface to optimize the local file access process. It addresses pain points such as errors caused by manual path entry, the loss of context for copied content, and conflicts in the image upload workflow. The plugin allows users to display files (including images, text, and folders) via drag-and-drop or paste, presenting them as native reference bubbles or within the chip bar above. Upon sending, it automatically generates references containing absolute paths, allowing the Agent to read the files directly rather than just processing uploaded data. Key features include: support for arbitrary file drag-and-drop and paste, insertion at the cursor when the input box is focused, and display in the chip bar when not focused; rendering file cards in message bubbles after sending; providing a `dropped_files` tool for the Agent to query unsent files; and compatibility with DSH Desktop's Electron preloader.