feat: Add API endpoint for managing categories

app/schemas/category.py

@@ -0,0 +1,17 @@
+from pydantic import BaseModel, Field, ConfigDict
+
+
+class CategoryBase(BaseModel):
+    name: str = Field(
+        ..., description="Unique category name", min_length=1, max_length=100
+    )
+
+
+class CategoryCreate(CategoryBase):
+    pass
+
+
+class CategoryResponse(CategoryBase):
+    id: int
+
+    model_config = ConfigDict(from_attributes=True)