GHSA-v847-hxxw-3pxg: PraisonAI recipe.run_stream skips dangerous-tool policy enforcement

PraisonAI recipe execution blocks default-denied dangerous tools unless the caller explicitly passes allow_dangerous_tools=True. The normal recipe.run() path enforces this with _check_tool_policy(). The streaming path, recipe.run_stream(), loads the same recipe, checks dependencies, and then calls _execute_recipe() without running the dangerous-tool policy check.

As a result, a recipe that honestly declares execute_command in TEMPLATE.yaml requires.tools is denied by recipe.run(), but reaches the execution engine through recipe.run_stream() with allow_dangerous_tools=False.

The local PoV uses a harmless printf canary, explicitly unsets PRAISONAI_AUTO_APPROVE, and avoids network access.