Add Temporal MCP transport samples

[brianstrauch]

Summary

• add a standalone temporal_mcp project pinned to temporalio-mcp==0.2.0
• demonstrate durable MCP tools, prompts, and resources
• support in-process, stdio, and streamable HTTP transports
• add credential-free end-to-end tests for every transport

Validation

• Ruff, formatting, mypy, and pytest pass on Python 3.10 and 3.14
• all three transports pass end-to-end against a local Temporal test server
• lockfile passes uv lock --check