Clearer AI redlining, with inline comments and the agent's own tracked changes

🔧 Improvements

• When the agent reviews one of your documents, it now leaves a comment on each issue it finds.
• The agent now has its own Track changes setting, separate from yours.
• Reminders now appear on the action they relate to, instead of in a separate tab.
• You can now paste or attach screenshots in chat, and the agent reads what's in them.

🐞 Fixes

• The task list now stays folded when the agent replies, so the reply stays in view.
• Word downloads now show your name on your tracked changes and on the agent's comments.