docs: use InjectedStore in semantic search guide

[jsambuo]

When I tried to follow the How-to guide for How to add semantic search to your agent's memory using create_react_agent, I got this error message when my agent used the tool:

1 validation error for upsert_memory
store
  Field required [type=missing, input_value={'content': '@jimmy works...ny.', 'memory_id': None}, input_type=dict]
    For further information visit https://errors.pydantic.dev/2.10/v/missingTraceback (most recent call last):

  File "/usr/local/lib/python3.9/site-packages/langchain_core/tools/base.py", line 688, in run
    tool_args, tool_kwargs = self._to_args_and_kwargs(tool_input, tool_call_id)

  File "/usr/local/lib/python3.9/site-packages/langchain_core/tools/base.py", line 611, in _to_args_and_kwargs
    tool_input = self._parse_input(tool_input, tool_call_id)

  File "/usr/local/lib/python3.9/site-packages/langchain_core/tools/base.py", line 532, in _parse_input
    result = input_args.model_validate(tool_input)

  File "/usr/local/lib/python3.9/site-packages/pydantic/main.py", line 627, in model_validate
    return cls.__pydantic_validator__.validate_python(

pydantic_core._pydantic_core.ValidationError: 1 validation error for upsert_memory
store
  Field required [type=missing, input_value={'content': '@jimmy works...ny.', 'memory_id': None}, input_type=dict]
    For further information visit https://errors.pydantic.dev/2.10/v/missing

I believe it’s because the graph did not inject the store into the tool if we use InjectedToolArg.

When looking at the guide for How to pass runtime values to tools, it suggests to use InjectedStore with create_react_agent. After changing my code to use InjectedStore, my agent was able to save to the store.