Add standalone CHI HN-F functional node implementation

[Copilot]

• Update hn/chi_hn_header.hpp — add includes for chi_joint.hpp and chi_xact_state.hpp
• Update hn/chi_hn.hpp:
  • Add addr_value_t typedef and std::shared_ptr<Xact::Xaction<config>> xaction field to PendingTxn
  • Add Xact::Global<config> global, rnJoints map (RNFJoint per RN), rnStateMaps map (RNCacheStateMap per RN) to Node
  • Add AddrValue() helper and RNJoint() / RNStateMap() accessor implementations
  • Wire CreateTransaction → rnJoint.NextTXREQ + rnStateMap.NextTXREQ
  • Wire IssueSnoop → rnJoint.NextRXSNP + rnStateMap.NextRXSNP
  • Wire HandleSnpResp → rnJoint.NextTXRSP + rnStateMap.NextTXRSP
  • Wire HandleCompAck → rnJoint.NextTXRSP
  • Wire HandleSnpRespData → rnJoint.NextTXDAT + rnStateMap.NextTXDAT
  • Wire HandleRNWriteData → rnJoint.NextTXDAT + rnStateMap.NextTXDAT
  • Wire SendComp → rnJoint.NextRXRSP + rnStateMap.NextRXRSP
  • Wire SendCompDBIDResp → rnJoint.NextRXRSP + rnStateMap.NextRXRSP
  • Wire SendCompData → rnJoint.NextRXDAT + rnStateMap.NextRXDAT
• Fix pre-existing framework bugs blocking compilation:
  • chi_joint.hpp: Joint::Joint() missing OnDeniedRequest(0) and OnDeniedResponse(0) initializers
  • chi_joint.hpp: JointDenied*Event constructors and member fields updated to use const& to properly handle temporaries (eliminates const_cast)
  • chi_xact_flit.hpp: SAMScope .value should be ->value (pointer type)
  • chi_xactions_base.hpp: GetFirstFrom/GetLastFrom/GetFirstTo/GetLastTo called IsFrom/IsTo on SubsequenceKey — should use subsequence[index].IsFrom/IsTo
  • chi_xactions_impl_AllocatingRead.hpp: missing GetDWTSrcIDSource / GetDWTTgtIDSource implementations
• Compile-verify and smoke test pass; CodeQL: 0 alerts