Python: Add a second demonstration tool to concurrent_builder_tool_approval sample

[moonbox3]

Summary

Update python/samples/03-workflows/tool-approval/concurrent_builder_tool_approval.py to include one more demonstration tool so the sample shows a richer concurrent approval scenario than a single approval-gated trade tool plus read-only helpers.

Context

Today the sample defines:

• read-only helper tools: get_stock_price, get_market_sentiment, get_portfolio_balance
• one approval-gated action: execute_trade

That makes the sample useful, but it does not show how agents choose between multiple actionable tools in the same concurrent workflow.

Proposed change

Add another domain-appropriate tool to the sample. A good default would be set_stop_loss(symbol: str, stop_price: float) -> str, marked with approval_mode="always_require".

Then update the sample instructions, prompt, and sample output so at least one agent may use either:

• execute_trade
• set_stop_loss

Why this helps

• Demonstrates that concurrent workflows can surface approval requests for different tools, not just repeated calls to the same tool.
• Makes the sample feel more realistic for trading and risk-management scenarios.
• Gives readers a better example of handling multiple pending approvals in one event-processing loop.

Acceptance criteria

• python/samples/03-workflows/tool-approval/concurrent_builder_tool_approval.py defines one additional demonstration tool.
• The new tool is included in both agents tools=` lists.
• The sample docstring, comments, and sample output are updated to mention the additional tool and expected behavior.
• The sample still clearly demonstrates concurrent approval handling end to end.