feat: Add shop system, befriend command, and level system

- Added configurable shop system with shop.json
- Created ShopManager class for modular shop handling
- Implemented level system with levels.json for difficulty scaling
- Added multiple duck spawn messages with random selection
- Enhanced message system with color placeholders
- Added ducks_befriended tracking separate from ducks_shot
- Updated help system and admin commands
- All systems tested and working correctly

levels.json

@@ -0,0 +1,80 @@
+{
+  "level_calculation": {
+    "method": "total_ducks",
+    "description": "Level based on total ducks interacted with (shot + befriended)"
+  },
+  "levels": {
+    "1": {
+      "name": "Duck Novice",
+      "min_ducks": 0,
+      "max_ducks": 9,
+      "befriend_success_rate": 85,
+      "accuracy_modifier": 5,
+      "duck_spawn_speed_modifier": 1.0,
+      "description": "Just starting out, ducks are trusting and easier to hit"
+    },
+    "2": {
+      "name": "Pond Visitor",
+      "min_ducks": 10,
+      "max_ducks": 24,
+      "befriend_success_rate": 80,
+      "accuracy_modifier": 0,
+      "duck_spawn_speed_modifier": 1.0,
+      "description": "Ducks are getting wary of you"
+    },
+    "3": {
+      "name": "Duck Hunter",
+      "min_ducks": 25,
+      "max_ducks": 49,
+      "befriend_success_rate": 75,
+      "accuracy_modifier": -5,
+      "duck_spawn_speed_modifier": 0.9,
+      "description": "Your reputation precedes you, ducks are more cautious"
+    },
+    "4": {
+      "name": "Wetland Stalker",
+      "min_ducks": 50,
+      "max_ducks": 99,
+      "befriend_success_rate": 70,
+      "accuracy_modifier": -10,
+      "duck_spawn_speed_modifier": 0.8,
+      "description": "Ducks flee at your approach, spawns are less frequent"
+    },
+    "5": {
+      "name": "Apex Predator",
+      "min_ducks": 100,
+      "max_ducks": 199,
+      "befriend_success_rate": 65,
+      "accuracy_modifier": -15,
+      "duck_spawn_speed_modifier": 0.7,
+      "description": "You're feared throughout the pond, ducks are very elusive"
+    },
+    "6": {
+      "name": "Duck Whisperer",
+      "min_ducks": 200,
+      "max_ducks": 399,
+      "befriend_success_rate": 60,
+      "accuracy_modifier": -20,
+      "duck_spawn_speed_modifier": 0.6,
+      "description": "Only the bravest ducks dare show themselves"
+    },
+    "7": {
+      "name": "Legendary Hunter",
+      "min_ducks": 400,
+      "max_ducks": 999,
+      "befriend_success_rate": 55,
+      "accuracy_modifier": -25,
+      "duck_spawn_speed_modifier": 0.5,
+      "description": "Duck folklore speaks of your prowess, they're extremely rare"
+    },
+    "8": {
+      "name": "Duck Deity",
+      "min_ducks": 1000,
+      "max_ducks": 999999,
+      "befriend_success_rate": 50,
+      "accuracy_modifier": -30,
+      "duck_spawn_speed_modifier": 0.4,
+      "description": "You've transcended mortal hunting, ducks are mythically scarce"
+    }
+  }
+}