feat: DaprMCPWorkflowClient and MCP workflow helpers

[sicoyle]

DaprMCPWorkflowClient and MCP Workflow Helpers

Add DaprMCPWorkflowClient to the Python SDK so all Python AI frameworks (dapr-agents, python-ai, etc.) can use it without depending on dapr-agents.

Scope

• DaprMCPWorkflowClient class: connect(server_name), get_all_tools(), call_tool()
• Starts ListTools/CallTool workflows via DaprClient.start_workflow
• Returns tools as typed objects with input schemas
• Workflow name construction (dapr.internal.mcp.<server>.<method>)
• JSON-compatible types matching proto definitions
• Reuse create_pydantic_model_from_schema for tool arg models
• Unit tests: mock DaprClient.start_workflow, assert correct workflow names/inputs
• Example usage and docs

Blocked by

• feat(mcp): add built-in mcp wf orchestration engine for mcpserver crd dapr#9731 (MCPServer in-process workflow engine)

Blocks

• dapr-agents MCPServer integration (consumes this client)
• diagridio/python-ai MCP support

Related

• feat(mcp): add proposal for new mcpserver resource proposals#100 (proposal - merged)