## Motivation and Context
Follow-up to https://github.com/modelcontextprotocol/ruby-sdk/pull/336
mcp gem 0.15.0 introduced an explicit `MCP::Client#connect` method for the stdio transport,
aligning with the Python and TypeScript SDKs which require explicit handshake calls regardless
of transport type:
- Python SDK: `ClientSession.initialize()`
https://github.com/modelcontextprotocol/python-sdk
- TypeScript SDK: `Client.connect(transport)`
https://github.com/modelcontextprotocol/typescript-sdk
This sample is updated to call `@mcp_client.connect` explicitly after creating the client,
demonstrating the recommended initialization pattern. The Gemfile constraint is bumped to `>= 0.15.0`
to require the new API.
## How Has This Been Tested?
Ran the sample against `weather-server-ruby` and confirmed the connection, tool listing,
and chat loop continue to work as expected.
## Breaking Changes
None. The change updates the sample to use the new explicit `connect` API,
which was added as a non-breaking addition in mcp gem 0.15.0.