Redesigned chat top bar and resizable sidebar

The chat top bar consolidates profile, admin, statistics, language, theme, and logout into a single account menu. The same menu and a clear Back to Chat button appear on every admin page, so administrators can switch language or theme and log out without leaving the panel.

The chat sidebar is now resizable: drag the edge to set its width, double-click to reset. The chosen width persists across sessions.

Scrollbars match the app color scheme rather than the default browser look, and the attach, input, and send controls in the message bar share a consistent height. Top-bar controls show hover tooltips for tools, help, notifications, the account menu, and Back to Chat.

The browser tab title now reflects the configured app name on the chat page.

No action required.