feat: Add API endpoint for managing categories

app/api/v1/categories.py

@@ -0,0 +1,35 @@
+from typing import List
+from fastapi import APIRouter, Depends, HTTPException, status
+from app.core.dependencies import get_category_service
+from app.core.exceptions import CategoryAlreadyExistsException
+from app.schemas.category import CategoryCreate, CategoryResponse
+from app.services.category_service import CategoryService
+
+router = APIRouter(prefix="/categories", tags=["categories"])
+
+
+@router.get("", response_model=List[CategoryResponse])
+async def list_categories(
+    service: CategoryService = Depends(get_category_service),
+):
+    """
+    Returns the list of all available categories ordered alphabetically.
+    """
+    return await service.list_categories()
+
+
+@router.post("", response_model=CategoryResponse, status_code=status.HTTP_201_CREATED)
+async def create_category(
+    category_in: CategoryCreate,
+    service: CategoryService = Depends(get_category_service),
+):
+    """
+    Creates a new custom category. The name must be unique.
+    """
+    try:
+        return await service.create_category(name=category_in.name)
+    except CategoryAlreadyExistsException as e:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail=str(e),
+        )