feat(frontend): add guild join flow, members panel, and channel-create member modal

src/auth/auth-context.ts

@@ -7,6 +7,7 @@ export type AuthContextValue = {
   login: (centerApiBase: string, email: string, password: string) => Promise<void>
   logout: () => Promise<void>
   ensureFreshToken: () => Promise<string | null>
+  refreshGuilds: () => Promise<void>
 }
 
 export const AuthContext = createContext<AuthContextValue | null>(null)