Fix achievement progression by moving Whispering Woods unlock

🎯 Achievement System Improvements:
- Pet Collector achievement (5 pets) now unlocks Whispering Woods
- Nature Explorer achievement (3 Grass species) no longer unlocks location
- Added 2 new Grass-type pets: Vinewrap and Bloomtail
- Updated Whispering Woods spawns to include new Grass pets

🐛 Problem Solved:
- Broke the catch-22 where players needed achievements to access locations
- But needed species from those locations to earn achievements
- Now players can progress naturally: 5 pets → Whispering Woods → more Grass species

🆕 New Pets:
- Vinewrap (Grass) - Defensive grass pet with vine abilities
- Bloomtail (Grass) - Fast grass pet with flower-based attacks

🔧 Updated Spawns:
- Whispering Woods: 3 Grass species (Leafy, Vinewrap, Bloomtail) + rare Flamey
- Players can now complete Nature Explorer achievement after accessing Whispering Woods

📚 Documentation:
- Updated README with new achievement progression
- Clarified unlock sequence and achievement relationships

This change makes the game progression much more logical and accessible for new players.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

config/pets.json

@@ -75,5 +75,27 @@
         "base_speed": 60,
         "evolution_level": null,
         "rarity": 3
+    },
+    {
+        "name": "Vinewrap",
+        "type1": "Grass",
+        "type2": null,
+        "base_hp": 55,
+        "base_attack": 45,
+        "base_defense": 70,
+        "base_speed": 40,
+        "evolution_level": null,
+        "rarity": 2
+    },
+    {
+        "name": "Bloomtail",
+        "type1": "Grass",
+        "type2": null,
+        "base_hp": 60,
+        "base_attack": 70,
+        "base_defense": 50,
+        "base_speed": 80,
+        "evolution_level": null,
+        "rarity": 2
     }
 ]