Upgrade Microsoft Semantic Kernel and audit `[KernelFunction]` methods

Upgrade Python SDK ≥ 1.39.4 and .NET SDK ≥ 1.71.0 (Microsoft Security Blog, 2026-05-07). Audit every [KernelFunction]-decorated method in your codebase for path, file-handle, raw-string-into-code, SQL, and URL parameter types; remove the decorator from anything that does not need to be LLM-callable. If upgrade is blocked, implement a Function Invocation Filter as a near-term mitigation. Apply the same hygiene check to LangChain, CrewAI, AutoGen and Haystack agents — the class of bug is not Microsoft-specific.