现有组件功能与Amesim组件比较对齐，补全功能；仿真服务启动环境检测，旧版json工程文件适配读取

native/components/modules/mechanics.c

@@ -1,6 +1,15 @@
 #include "kernels.h"
 #include <math.h>
 
+double native_dry_friction(double velocity, double static_share, double coulomb,
+                           double stiction, double stribeck_velocity, int stribeck,
+                           double mode) {
+    if (fabs(mode)<.5) return -static_share;
+    double resistance=coulomb;
+    if (stribeck) resistance+=(stiction-coulomb)*exp(-3*fabs(velocity)/stribeck_velocity);
+    return mode>0 ? -resistance : resistance;
+}
+
 double native_contact(double penetration, double velocity, double stiffness,
                       double damping, double pdis, int signed_force) {
     if (penetration <= 0) return 0;
@@ -21,7 +30,5 @@ void native_stop_motion(double x, double v, double lower, double upper,
 
 double native_limit_force(double penetration, double velocity, double stiffness,
                           double damping, double depth, int signed_force) {
-    if(penetration<=0) return 0;
-    double force=stiffness*penetration+(depth>0?fmin(penetration/depth,1):1)*damping*velocity;
-    return signed_force==1?force:fmax(force,0);
+    return native_contact(penetration, velocity, stiffness, damping, depth, signed_force);
 }

native/components/modules/properties.c

@@ -239,3 +239,17 @@ int native_medium_gas(const NativeMedium *medium, double m, double U, double V,
 int native_medium_gas_context(NativePropertyCache *cache,const NativeMedium *m,double mass,double U,double V,NativeGas *g) {
     int ok=native_medium_gas(m,mass,U,V,g);if(ok)remember_gas(cache,m,g);return ok;
 }
+
+int native_polytropic_gas_context(NativePropertyCache *cache,const NativeMedium *m,
+                                  double mass,double T,double V,NativeGas *g) {
+    /* Amesim's polytropic storage uses ideal-gas mass even when the selected
+       gas supplies real-fluid enthalpy/density to the connected resistances. */
+    if(!(mass>0 && T>0 && V>0))return 0;
+    g->T=T;g->p=mass*m->R*T/V;
+    g->rho=native_density_context(cache,m,g->p,T);
+    double dt=T-m->Tref;
+    g->h=m->real_helium?h_ideal(T)+h_departure(g->p,T):m->cp*T+.5*m->slope*dt*dt;
+    g->u=g->h-g->p/g->rho;
+    if(!(g->p>0 && g->rho>0 && isfinite(g->p) && isfinite(g->h) && isfinite(g->u)))return 0;
+    remember_gas(cache,m,g);return 1;
+}

native/components/modules/signal.c

@@ -2,9 +2,11 @@
 #include <math.h>
 
 double native_signal(double t, double start, int stages, int cyclic, const double *data) {
-    double elapsed = fmax(t-start,0), duration = 0, offset = 0;
+    if (t < start) return data[0];
+    double elapsed = t-start, duration = 0, offset = 0;
     for (int i=0;i<stages;i++) duration += data[16+i];
     if (cyclic && duration > 0) elapsed = fmod(elapsed,duration);
+    else if (elapsed >= duration) return data[8+stages-1];
     for (int i=0;i<stages;i++) {
         double d = data[16+i];
         if (elapsed < offset+d || i == stages-1)
@@ -18,7 +20,9 @@ double native_signal_break(double t, double end, double start, int stages,
                            int cyclic, const double *data) {
     double duration=0, offset=0, result=end;
     for (int i=0;i<stages;i++) duration += data[16+i];
-    for (int i=0;i<stages;i++) {
+    /* A cyclic endpoint is already the next cycle's start. Listing both can
+       create two nearly equal floating-point break times for one event. */
+    for (int i=0;i<stages+(cyclic?0:1);i++) {
         double event=start+offset;
         if (cyclic && duration > 0 && event <= t) {
             double cycle=fmax(0,floor((t-event)/duration)+1);
@@ -26,7 +30,7 @@ double native_signal_break(double t, double end, double start, int stages,
             if (event <= t) event += duration;
         }
         if (event > t) result=fmin(result,event);
-        offset += data[16+i];
+        if (i < stages) offset += data[16+i];
     }
     return result;
 }