[WASM] Integration tests: MCP clients

[awsarron]

Parent issue

strands-agents/sdk-typescript#1104

Scope

Write integration tests validating MCP (Model Context Protocol) client integration:

• StdioMcpTransport() - local command-line MCP servers
• StreamableHttpMcpTransport() - HTTP-based MCP servers
• SseMcpTransport() - Server-Sent Events transport
• Tool discovery from MCP servers
• Tool invocation via MCP
• Multiple MCP clients on a single agent

Context

MCP clients run inside the WASM guest (TS SDK's MCP implementation). The Python side provides transport configuration that crosses the WIT boundary. The TS SDK manages the MCP connection lifecycle.

Key areas:

• Transport config serializes correctly through WIT
• MCP server tools appear in the agent's tool set
• Agent can invoke MCP tools during conversation
• Multiple MCP servers compose correctly

Done when

• Stdio transport connects to a local MCP server
• StreamableHttp transport connects to an HTTP MCP server
• Tools from MCP servers are discoverable by the agent
• Agent successfully invokes MCP tools in conversation
• Multiple MCP clients work together on one agent