Attachments: Folder Attach + Size Warnings (M2 #20)

[ddroid]

What to build

Add folder attachment support: when a user attaches a folder, Ronin shows the file listing and lets the user select which files to include (not a full recursive index). This gives users explicit control over what context is attached from a directory.

Add attachment size warnings across all attachment types. Before sending, warn the user if attached content is large enough to significantly consume the context window.

Acceptance criteria

• User can attach a folder via @folder or drag-and-drop
• Folder attachment shows a file listing of the directory contents
• User can select/deselect individual files from the listing
• Only selected files are included as attachment content
• Deep/recursive listing is bounded or paginated for large directories
• Attachment size warnings appear when total attachment content exceeds a configurable threshold
• Size warning shows the approximate token/character impact on the context window
• User can proceed past the warning or remove attachments to reduce size
• Size warnings work for all attachment types (file, image, clipboard, folder)
• Tests cover folder file selection and size warning thresholds

Blocked by

• Attachments: Screenshot + Image + Better File Preview (M2 #19) #38 (Attachments: Screenshot + Image + Better File Preview)