revert: "chore(cleanup)!: remove tool_runtime.rag_tool" (#3877)

Reverts llamastack/llama-stack#3871

This PR broke RAG (even from Responses -- there _is_ a dependency)

llama_stack/core/server/routes.py

@@ -13,6 +13,7 @@ from aiohttp import hdrs
 from starlette.routing import Route
 
 from llama_stack.apis.datatypes import Api, ExternalApiSpec
+from llama_stack.apis.tools import RAGToolRuntime, SpecialToolGroup
 from llama_stack.core.resolver import api_protocol_map
 from llama_stack.schema_utils import WebMethod
 
@@ -24,16 +25,33 @@ RouteImpls = dict[str, PathImpl]
 RouteMatch = tuple[EndpointFunc, PathParams, str, WebMethod]
 
 
+def toolgroup_protocol_map():
+    return {
+        SpecialToolGroup.rag_tool: RAGToolRuntime,
+    }
+
+
 def get_all_api_routes(
     external_apis: dict[Api, ExternalApiSpec] | None = None,
 ) -> dict[Api, list[tuple[Route, WebMethod]]]:
     apis = {}
 
     protocols = api_protocol_map(external_apis)
+    toolgroup_protocols = toolgroup_protocol_map()
     for api, protocol in protocols.items():
         routes = []
         protocol_methods = inspect.getmembers(protocol, predicate=inspect.isfunction)
 
+        # HACK ALERT
+        if api == Api.tool_runtime:
+            for tool_group in SpecialToolGroup:
+                sub_protocol = toolgroup_protocols[tool_group]
+                sub_protocol_methods = inspect.getmembers(sub_protocol, predicate=inspect.isfunction)
+                for name, method in sub_protocol_methods:
+                    if not hasattr(method, "__webmethod__"):
+                        continue
+                    protocol_methods.append((f"{tool_group.value}.{name}", method))
+
         for name, method in protocol_methods:
             # Get all webmethods for this method (supports multiple decorators)
             webmethods = getattr(method, "__webmethods__", [])