Refactors the browser UI into a reusable `CO_Browser.create()` module and adds embedded modal styling so MULTIPLAYER opens inside the main menu instead of swapping to a separate view. Updates main-menu JS/CSS to host, animate, and route input for the browser panel while keeping nav and prompts in sync. On the C++ side, PrismaUI now drives browser show/hide and event dispatch through the main menu view, and `ServerBrowserBridge::SetView()` was added so bridge events target the active host view.
