docs: add OpenAPI-first wiki (overview, components, use cases for templates/client/codegen, design, security, error handling, testing) and refresh lib docs index

openapi_first/templates/crud_app/data.py

@@ -33,7 +33,7 @@ _items: Dict[int, dict] = {
 _next_id = 3
 
 
-def list_items():
+def list_items() -> list[dict]:
     """
     Return all items in the data store.
 
@@ -48,7 +48,7 @@ def list_items():
     return list(_items.values())
 
 
-def get_item(item_id: int):
+def get_item(item_id: int) -> dict:
     """
     Retrieve a single item by ID.
 
@@ -68,7 +68,7 @@ def get_item(item_id: int):
     return _items[item_id]
 
 
-def create_item(payload: dict):
+def create_item(payload: dict) -> dict:
     """
     Create a new item in the data store.
 
@@ -92,7 +92,7 @@ def create_item(payload: dict):
     return item
 
 
-def update_item(item_id: int, payload: dict):
+def update_item(item_id: int, payload: dict) -> dict:
     """
     Replace an existing item in the data store.