Add AI tools example with SPIFFE identity and in-process OPA/WASM authorization (#269)

A Camel LangChain4j agent whose tools are authorized before they run by an Open Policy Agent policy evaluated in-process as WebAssembly (the camel-opa wasm client), with SPIFFE (camel-spiffe) authenticating the calling workload. It shows prompt-injection containment: a caller talked into asking the model for a refund is denied by the guard, so the refund never happens.