docs(adapter): fix LangChain README example to use the tool's actual result keys

[feizhuzheng]

Problem

The LangChain adapter quickstart in python/uagents-adapter/README.md ends with:

print(f"Created uAgent '{result['agent_name']}' with address {result['agent_address']} on port {result['agent_port']}")

But LangchainRegisterTool._run() returns the agent_info dict built in src/uagents_adapter/langchain/tools.py, whose keys are name (L136), port (L138) and address (set at L154) — there is no agent_name, agent_address or agent_port anywhere in that module. So copy-pasting the example and running it raises KeyError: 'agent_name' on that final line, right after the agent successfully starts.

Evidence this is a copy-paste slip, not the intended contract

The CrewAI adapter section has an identical-looking print line (README.md a bit further down) that uses the same agent_name/agent_address/agent_port keys — and there it is correct, because CrewaiRegisterTool in src/uagents_adapter/crewai/tools.py actually builds its result dict with those agent_* keys. The LangChain snippet was evidently adapted from the CrewAI one without updating the key names to match LangchainRegisterTool's different return shape (name/address/port).

Fix

Align the LangChain example with the keys that tool actually returns — a one-line, docs-only change to the LangChain print statement:

print(f"Created uAgent '{result['name']}' with address {result['address']} on port {result['port']}")

The CrewAI example is left untouched, since its keys are already right.

Alternative

If you would rather keep the two adapters' documented output identical, the other direction is to make LangchainRegisterTool emit agent_name/agent_address/agent_port too, unifying both adapters' result contracts. I went with the minimal docs-side fix here since it is the safest and does not change any public return shape, but happy to switch to the code-side alignment if you prefer that.

Verification

• LangchainRegisterTool._run returns agent_info; its keys are set to name/port/address in langchain/tools.py, with no agent_* keys in the file.
• The neighboring CrewAI print line uses agent_* and matches crewai/tools.py, which does define those keys — confirming the mismatch is isolated to the LangChain snippet.

Thanks for uAgents!

[feizhuzheng]

Closing this as a duplicate of #933, which makes the same one-line fix. Apologies for the double PR — please review #933. Thanks!