handlePageTextQueryResponse() now collects pages into bookPages_ vector
instead of dumping lines to system chat. Multi-page items (nextPageId != 0)
are automatically chained by requesting subsequent pages. The book window
opens automatically when pages arrive, shows formatted text in a parchment-
styled ImGui window with Prev/Next page navigation and a Close button.
SMSG_READ_ITEM_OK clears bookPages_ so each item read starts fresh;
handleGameObjectPageText() does the same before querying the first page.
Closes the long-standing issue where reading scrolls and tattered notes
spammed many separate chat messages instead of showing a readable UI.
5883654e1e