Fix(deltaspin): fix cal_escon segfault, cal_pre_HR memory leak, and current_spin propagation

Bug fixes:
- cal_escon(): add lambda_/Mi_ empty check to prevent segfault when uninitialized
  (also preserves is_Mi_converged guard for behavioral compatibility)
- cal_pre_HR(): delete old pre_hr allocations before reallocating to prevent
  memory leak when DeltaSpin is reinitialized
- operator_lcao.cpp: propagate current_spin to next operator in chain so all
  operators share the same spin state set by HamiltLCAO::updateHk

Test refs regenerated for 17_DS_DFTU enabled cases.

Author: dyzheng

source/source_lcao/module_deltaspin/spin_constrain.cpp

@@ -45,7 +45,7 @@ template <typename TK>
 double SpinConstrain<TK>::cal_escon()
 {
     this->escon_ = 0.0;
-    if (!this->is_Mi_converged)
+    if (this->lambda_.empty() || this->Mi_.empty() || !this->is_Mi_converged)
     {
         return this->escon_;
     }

source/source_lcao/module_operator_lcao/dspin_lcao.cpp

@@ -224,6 +224,10 @@ void hamilt::DeltaSpin<hamilt::OperatorLCAO<TK, TR>>::cal_pre_HR()
     }
     this->paraV = this->hR->get_paraV();
     ModuleBase::timer::start("DeltaSpin", "cal_pre_HR");
+    for (auto& hr : this->pre_hr)
+    {
+        delete hr;
+    }
     this->pre_hr.clear();
     this->pre_hr.resize(this->ucell->nat, nullptr);
 

source/source_lcao/module_operator_lcao/operator_lcao.cpp

@@ -79,6 +79,9 @@ void OperatorLCAO<TK, TR>::init(const int ik_in) {
             this->hR->set_zero();
         }
     }
+    if (this->next_op != nullptr) {
+        dynamic_cast<OperatorLCAO<TK, TR>*>(this->next_op)->current_spin = this->current_spin;
+    }
     switch (this->cal_type) {
         case calculation_type::lcao_overlap: {
             // cal_type=lcao_overlap refer to overlap matrix operators, which are