feat: add daily challenges system

Three PST-midnight-resetting challenges generated deterministically per
day from click, boss, quest, and prestige types. Progress tracked
server-side for bosses and prestige, client-side for clicks and quests.
Crystal rewards awarded on completion and preserved through prestige resets.

apps/web/src/context/GameContext.tsx

@@ -14,6 +14,7 @@ import {
   saveGame,
 } from "../api/client.js";
 import { RESOURCE_CAP, applyTick, calculateClickPower } from "../engine/tick.js";
+import { updateChallengeProgress } from "../utils/dailyChallenges.js";
 import { formatNumber as formatNumberUtil } from "../utils/format.js";
 
 
@@ -245,14 +246,28 @@ export const GameProvider = ({ children }: { children: React.ReactNode }): React
       if (!prev) return prev;
       const clickPower = calculateClickPower(prev);
       const newGold = Math.min(prev.resources.gold + clickPower, RESOURCE_CAP);
+
+      let updatedDailyChallenges = prev.dailyChallenges;
+      let challengeCrystals = 0;
+      if (updatedDailyChallenges) {
+        const result = updateChallengeProgress(updatedDailyChallenges, "clicks", 1);
+        updatedDailyChallenges = result.updatedChallenges;
+        challengeCrystals = result.crystalsAwarded;
+      }
+
       return {
         ...prev,
-        resources: { ...prev.resources, gold: newGold },
+        resources: {
+          ...prev.resources,
+          gold: newGold,
+          crystals: Math.min(prev.resources.crystals + challengeCrystals, RESOURCE_CAP),
+        },
         player: {
           ...prev.player,
           totalGoldEarned: prev.player.totalGoldEarned + clickPower,
           totalClicks: prev.player.totalClicks + 1,
         },
+        dailyChallenges: updatedDailyChallenges,
       };
     });
   }, []);