Add full retention systems: daily hub, raids, prestige, seasons

- Graze slow-mo, perfect-wave FRENZY (x3 amber), ghost records,
  dynamic hunter titles
- Daily Hub: 7-day login calendar, animated lucky wheel, boss chest
  keys, pet eggs with rarity tiers + pity counter and real stat perks
- Seeded daily challenge (server-consistent modifiers, local top-5),
  hourly Golden Herd stampede, weekly Raid Colossus with damage tiers
- Rebirth prestige with Ancient Gem permanent perk shop
- Weapon mastery stars (+2%/level), bestiary milestone gems
- Weekly season points with Bronze..Diamond rank badges
- Shareable PNG result card on game over

js/data.js

@@ -81,6 +81,39 @@
                 vi: 'Thái Dương — ánh sáng nguyên thủy' }
   };
 
+  /* ---------------- Daily challenge modifiers ---------------- */
+  US.DAILY_MOD_POOL = [
+    { id: 'fastfoes',  en: 'Fast Foes ×1.25',   vi: 'Quái Nhanh ×1.25' },
+    { id: 'glasshero', en: 'Glass Hero ×0.6 HP', vi: 'Thủy Tinh Hero ×0.6 HP' },
+    { id: 'richherds', en: 'Rich Herds ×2 amber', vi: 'Đàn Thú Giàu ×2 hổ phách' },
+    { id: 'swarm',     en: 'Swarm ×1.4 budget',  vi: 'Bầy Đàn ×1.4 ngân sách' },
+    { id: 'venomwind', en: 'Venom +30% dmg',     vi: 'Nọc Độc +30% sát thương' }
+  ];
+
+  /* ---------------- Pets by rarity ---------------- */
+  US.PETS = {
+    common: [
+      { name: 'Cơm Nếp', color: '#c98a3d' },
+      { name: 'Xanh Lá', color: '#5f8f3e' },
+      { name: 'Bonnie', color: '#b05f8f' },
+      { name: 'Mập Mạp', color: '#7a5230' }
+    ],
+    rare: [
+      { name: 'Tia Chớp', color: '#58a55c', perk: { rof: 0.06 } },
+      { name: 'Sấm Rền', color: '#9fd8ff', perk: { dmg: 0.05 } }
+    ],
+    legendary: [
+      { name: 'Rồng Lửa', color: '#ff6b35', perk: { dmg: 0.10, rof: 0.05 } },
+      { name: 'Băng Giá', color: '#aee3ff', perk: { hp: 15, gold: 0.10 } }
+    ]
+  };
+
+  // login calendar rewards (day 1..7)
+  US.LOGIN_REWARDS = [
+    { coins: 250 }, { chestKey: 1 }, { coins: 400 }, { gems: 15 },
+    { coins: 600 }, { gems: 25 }, { egg: 'rare', gems: 50 }
+  ];
+
   /* ---------------- Beasts ---------------- */
   // contact = dps on touch; value feeds heat/score; cost feeds wave budget
   US.ENEMIES = {