Bind online session browser to canvas, drop IMGUI
- OnlineSessionManager: remove OnGUI/IMGUI state; now a logic-only layer
exposing Host/Refresh/Join/Disconnect plus Status/IsBusy/IsConnected/
InSession/Sessions and Changed/SessionsChanged events
- OnlineSessionBrowserUI (new): drives the Servers canvas — 4 buttons,
session list from Entry Template clones (name + players), row selection,
state-driven interactability, status footer
- Main scene: attach binder, add status footer line, wire 8 refs; dev
bootstrap panel disabled
- Online Session Manager.prefab (new)
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>