Add skill management system: implement Skill and PetSkill models, create SkillController, and update ApplicationDbContext for skills

Models/Skill.cs

@@ -0,0 +1,82 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace PetCompanion.Models
+{
+    public enum SkillType
+    {
+        GROUND,
+        GRAND
+    }
+
+    public enum SkillTier
+    {
+        I = 1,
+        II = 2,
+        III = 3
+    }
+
+    public class Skill
+    {
+        [Key]
+        public int Id { get; set; }
+        public string Name { get; set; }
+        public string Description { get; set; }
+        public SkillType Type { get; set; }
+        public int PointsCost { get; set; }
+        public string Icon { get; set; }
+        public List<int>? SkillsIdRequired { get; set; }
+        public virtual ICollection<SkillEffect> Effects { get; set; }
+        public virtual ICollection<PetSkill> PetSkills { get; set; }
+    }
+
+    public class SkillEffect
+    {
+        [Key]
+        public int Id { get; set; }
+        public int SkillId { get; set; }
+        public virtual Skill Skill { get; set; }
+        public SkillTier Tier { get; set; }
+        public string Effect { get; set; }
+        public decimal Value { get; set; }
+
+        public void PetSkillUpgrade(ref Pet pet)
+        {
+            switch (Effect)
+            {
+                case "MaxHealth":
+                    pet.MaxHealth += (int)Value;
+                    break;
+                case "MaxIntelligence":
+                    pet.Stats.MaxIntelligence += (int)Value;
+                    break;
+                case "MaxStrength":
+                    pet.Stats.MaxStrength += (int)Value;
+                    break;
+                case "MaxCharisma":
+                    pet.Stats.MaxCharisma += (int)Value;
+                    break;
+                case "Luck":
+                    pet.Stats.Luck += (int)Value;
+                    break;
+                case "Agility":
+                    pet.Stats.Agility += (int)Value;
+                    break;
+                case "Perception":
+                    pet.Stats.Perception += (int)Value;
+                    break;
+                    // Add more effects as needed
+            }
+        }
+    }
+
+    public class PetSkill
+    {
+        [Key]
+        public int Id { get; set; }
+        public string PetId { get; set; }
+        public virtual Pet Pet { get; set; }
+        public int SkillId { get; set; }
+        public virtual Skill Skill { get; set; }
+        public SkillTier CurrentTier { get; set; }
+    }
+}