guild upgrades, enum for quest ranks and quests now persist while clicking onto another tab

src/classes/Guild.ts

@@ -1,9 +1,36 @@
 export class Guild {
     gold: number;
     level: number;
+    displayUpgradeCost: number|string;
 
     constructor(level: number, gold: number) {
         this.gold = gold;
         this.level = level;
+        this.displayUpgradeCost = this.getUpgradeCost() ?? "Max level";
     }
-}
+
+    upgrade(): void {
+        const cost = this.getUpgradeCost();
+        if (cost === null) return;
+        if (this.gold < cost) return;
+        this.gold -= cost;
+        this.level += 1;
+        if (this.level > 7) {
+            this.displayUpgradeCost = "Max level";
+        }
+    }
+
+    getUpgradeCost(): number|null {
+        return upgradeCosts[this.level] ?? null;
+    }
+}
+
+const upgradeCosts = {
+    "1": 1000,
+    "2": 2500,
+    "3": 5000,
+    "4": 10000,
+    "5": 25000,
+    "6": 50000,
+    "7": 100000,
+} as {[index:string]: number}