refactor: drop sqlite fallback and admin mode

web/src/lib/config.ts

@@ -1,6 +1,8 @@
 export interface SystemConfig {
-  admin_mode: boolean
   beta_mode: boolean
+  default_coins?: string[]
+  btc_eth_leverage?: number
+  altcoin_leverage?: number
 }
 
 let configPromise: Promise<SystemConfig> | null = null