Feature Request: Support drag-and-drop file upload in VS Code extension

Problem

The VS Code extension does not support dragging files into the chat panel to attach them. The desktop app and web app both support this feature.

Proposed Solution

Implement HTML5 drag-and-drop (dragover/drop events) in the webview chat panel, allowing users to drag files from the VS Code explorer or the system file manager directly into the chat input area to attach them.

Why

• Desktop and web versions already support drag-and-drop
• VS Code webviews fully support HTML5 drag/drop events natively
• React (which the extension webview uses) already has the event hooks registered (onDragOver, onDrop, etc.) — they just need handler implementation
• Provides feature parity across all Claude Code surfaces

Extension Version

anthropic.claude-code 2.1.175 (darwin-x64)