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/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;
 }