Buddy's Environment advertises sideChats: true although it offers none #159

What

Buddy's T3 Code (an Environment whose config has lazurioBuddy) offers no side chats: the web hides them on Buddy's surface (sideChatsOffered, row 25), and the server refuses thread.fork from Buddy (row 25's command guard). But the Environment's descriptor still advertises sideChats: true (apps/server/src/environment/ServerEnvironment.ts:236, upstream's value).

No client reads it in a way that matters today: the web gates side chats per surface, and mobile does not create side chats on v0.1.6.

Fix (optional)

Advertise sideChats: false on Buddy's Environment, so a future client that reads the capability does not offer what the server refuses.

Found by the independent check of the v0.1.6 rebuild (#148).