[Feature Request] Open the AI document chat as a full page/tab instead of a small overlay window

Description On 3.0.0 (beta), the AI document chat opens as a small overlay window anchored to the document view. The feature itself works well, but the overlay form factor limits it: • Long answers are cramped — RAG answers with quotes or multi-paragraph explanations require lots of scrolling inside a tiny viewport. • No side-by-side reading — when the model references document content, you want the chat next to the full document preview, not floating over it. • Conversation review is hard — going back and forth in a longer Q&A session inside a small scroll area is tedious. • Small screens — on tablets/phones the overlay leaves very little usable space. Proposal Offer a full-page presentation for the chat (the overlay could stay as the quick-access default): 1. An expand button on the chat overlay that opens the same conversation as a full page/route (e.g. /documents/{id}/chat), ideally with a split view: document preview left, chat right. 2. Optionall…