Guild bank: in-game commands, guild market listings and purchases, shop sales to the bank, guild payments

crates/shared/src/lib.rs

@@ -578,6 +578,9 @@ pub struct MarketListing {
     pub amount: i32,
     pub price: f64,
     pub created_at: String,
+    /// Set when a guild is selling; the sale is paid into its bank.
+    #[serde(default)]
+    pub seller_guild_tag: Option<String>,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Default)]