feat(moderation): Handle online moderation notices

[tintinhamans]

Adds client-side handling for moderation events.

• handles WebSocket moderation notices for bans, kicks, and rate-limit messages
• shows clear ban/kick dialogs with optional server-provided reasons and a Discord support link
• preserves moderation teardown reasons so generic disconnect dialogs do not overwrite them
• surfaces rate-limit notices in the appropriate lobby or room chat
• parses ban reasons from login and token-refresh responses
• adds labeled message-box buttons for the moderation dialogs
• records server support for moderation commands from the room-list response