fix(tutorials): pin mcp<2 for uvx-spawned MCP servers in 020_state_machine

mcp 2.0.0 renamed `McpError` to `MCPError` and split types out into a
separate `mcp_types` package. `mcp-server-time` and `mcp-server-fetch`
still import the 1.x name, so both now die at import:

    ImportError: cannot import name 'McpError' from 'mcp.shared.exceptions'
    ... -> mcp.shared.exceptions.McpError: Connection closed

uvx builds each server its own isolated environment and resolves `mcp`
unpinned there, so the `mcp==1.23.0` this project installs does not apply.
With every server dead the deep research agent emits "Starting deep
research..." and then makes zero tool calls, so test_agent.py's
`uses_tool_requests` assertion fails (and the streaming test times out
waiting for the same content).

This is why the job passed at 03:48 today and failed at 14:08 with no
code change in between: mcp 2.0.0 landed in the gap.

Constraining uvx to mcp<2 restores all three servers. Verified by
completing an MCP initialize + tools/list handshake against the exact
argv this file now produces:

    mcp-server-time          tools=['get_current_time', 'convert_time']
    openai-websearch-mcp     tools=['openai_web_search']
    mcp-server-fetch         tools=['fetch']

The 30s test timeout is left alone; both tests passed in 21.1s total
when the servers worked.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: declan-scale

examples/tutorials/10_async/10_temporal/020_state_machine/project/workflows/deep_research/performing_deep_research.py

@@ -13,21 +13,28 @@
 
 logger = make_logger(__name__)
 
+# These reference MCP servers still import the mcp 1.x API (``McpError``), which
+# mcp 2.0.0 renamed to ``MCPError``. uvx gives each server its own isolated env and
+# resolves ``mcp`` unpinned there, ignoring the version this project pins, so without
+# this constraint every server dies at import and the agent silently makes zero tool
+# calls. Drop the pin once the servers support mcp 2.x.
+_MCP_PIN = ["--with", "mcp<2"]
+
 MCP_SERVERS = [
     StdioServerParameters(
         command="uvx",
-        args=["mcp-server-time", "--local-timezone", "America/Los_Angeles"],
+        args=[*_MCP_PIN, "mcp-server-time", "--local-timezone", "America/Los_Angeles"],
     ),
     StdioServerParameters(
         command="uvx",
-        args=["openai-websearch-mcp"],
+        args=[*_MCP_PIN, "openai-websearch-mcp"],
         env={
             "OPENAI_API_KEY": os.environ.get("OPENAI_API_KEY", "")
         }
     ),
     StdioServerParameters(
         command="uvx",
-        args=["mcp-server-fetch"],
+        args=[*_MCP_PIN, "mcp-server-fetch"],
     ),
 ]