Fix broken custom chats widths feature (#24)

[itsmartashub]

Closes #24

• Add new css var --dsxChatsWrapperPadding to override the original dynamic Deepseek padding based on --message-list-max-width:

._8525d44 .ca1ef5b2 {
		padding: 0 calc((100% - var(--message-list-max-width)) / 2);
		...
}