修复循环信号与事件采样并接入 LSTP 接触定位，补充八路验证及复用实验

相较上一版 Jacobian 确定性复用更新，本次补齐事件边界一致性、结果两侧采样及接触事件定位；保留已有物性复用和组件力学公式。

- 统一 UD00 信号求值与下一事件查询的绝对时间边界，修复循环边界浮点舍入导致的阶段错位、重复或漏报，并覆盖零时长、多阶段及长周期场景。
- 引入原生输出语义 v2：保留规则网格真实时间，补充内部时间事件和状态事件的左邻及事件后采样，按保存时间、状态和离散模式重放结果。
- 两条代码生成路径均发出 LSTP 接触描述，默认定位间隙过零及非负力模式的力截断；仅在接受事件时更新防重复记录，增加 contactEvents 诊断计数。
- 补充 MASS/LSTP 独立事件实验、八路全曲线与驱动阶段配对评估，以及 Amesim 不连续点输出对照和力差定位报告；MASS 新增释放机制仍保留为独立实验。
- 保存局部 probe、context 访问与回退、shadow replay、R288 real skip/typed replay 及阀门数值尾部诊断工具和报告；未证明净收益的实验不启用为生产默认优化。
- 更新原生运行说明和元件建模规范，补充信号边界、输出语义、接触事件和实验依赖回归测试。

验证：五组专项回归共 34 项全部通过；37 个待提交 Python 文件语法检查通过；git diff --cached --check 通过。

app/simulation/native_codegen/compiler.py

@@ -373,6 +373,11 @@ def _compile_storage_anchored_program(network: SimulationNetwork) -> NativeProgr
         raise NativeCapabilityError(f"Native output coverage is incomplete: {sorted(missing)}")
 
     stops = [(si(c, "v"), c.xmin, c.xmax) for c in masses if int(c.stoptype) == 1]
+    from .contacts import contact_table
+    contact_source, contact_header = contact_table([
+        (si(mass_at(c, 'port_1'), 'v'), si(mass_at(c, 'port_2'), 'v'),
+         c.gap0, c.kcont, c.rcont, c.Pdis, int(c.discContactOption), 1)
+        for c in components if c.model_type == 'amesim_lstp00a'])
     stop_c = ",".join(f"{{{v},{_number(lo)},{_number(hi)},0,0,0,0}}" for v, lo, hi in stops) or "{0,0,0,0,0,0,0}"
     next_event = []
     for index, c in signal_specs:
@@ -384,6 +389,7 @@ def _compile_storage_anchored_program(network: SimulationNetwork) -> NativeProgr
     source = '\n'.join([
         '#include "model.h"', '#include <math.h>', *declarations,
         f"const NativeStop model_stops[{max(1,len(stops))}] = {{{stop_c}}};",
+        contact_source,
         f"const double model_atol[NSTATES] = {{{','.join(map(state_absolute_tolerance, state_keys))}}};",
         "const char *const model_output_keys[NOUTPUTS] = {" + ",".join(json.dumps(v.key, ensure_ascii=True) for v in variables) + "};",
         "int model_init(double *y) {", *init, "return 1; }",
@@ -408,6 +414,7 @@ int model_property_temperatures(double t,const double *y,NativePropertyTemperatu
 #define NSTATES {len(state_keys)}
 #define NOUTPUTS {len(variables)}
 #define NSTOPS {len(stops)}
+{contact_header}
 extern const NativeStop model_stops[{max(1,len(stops))}];
 extern const double model_atol[NSTATES];
 extern const char *const model_output_keys[NOUTPUTS];

app/simulation/native_codegen/contacts.py

@@ -0,0 +1,24 @@
+"""Emit state-only LSTP event descriptors for both native lowering paths."""
+from .compiler import _number
+
+
+def contact_table(contacts):
+    """Rows: velocity indices, gap, stiffness, damping, depth, force option,
+    subtract-first flag. Keep the force expression's floating operation order.
+    Position follows velocity in each reviewed mechanical state pair.
+    """
+    rows = []
+    for v1, v2, gap, stiffness, damping, depth, option, subtract_first in contacts:
+        rows.append('{' + ','.join((str(v1), str(v2), _number(gap),
+            _number(stiffness), _number(damping), _number(depth),
+            str(option), str(subtract_first))) + '}')
+    count = len(rows)
+    header = f'''#define NCONTACTS {count}
+typedef struct {{
+    int velocity1, velocity2;
+    double gap0, stiffness, damping, depth;
+    int signed_force, subtract_first;
+}} NativeContact;
+extern const NativeContact model_contacts[{max(1, count)}];'''
+    source = f'const NativeContact model_contacts[{max(1, count)}] = {{' + (','.join(rows) or '{0,0,0,0,0,0,0,0}') + '};'
+    return source, header

app/simulation/native_codegen/extended.py

@@ -723,6 +723,12 @@ def compile_extended_program(network):
         policy='immutable canonical baseline for gas, PH inversion, density and pipe roots; changed inputs recomputed',
         verification='uncached canonical dense differences')
     np,ng,nq=max(1,len(pgroups)),max(1,gas_count),max(1,len(pneu))
+    from .contacts import contact_table
+    contact_source, contact_header = contact_table([
+        (states[mass_groups[groups.find(ep(c, 'port_1'))][0].name, 'v'],
+         states[mass_groups[groups.find(ep(c, 'port_2'))][0].name, 'v'],
+         c.gap0, contact_stiffness(c), c.rcont, c.Pdis, int(c.discContactOption), 0)
+        for c in components if c.model_type == 'amesim_lstp00a'])
     # Advanced-friction reference runs at 5 N and 7 N confirm Amesim 2404's
     # 0.1% breakaway hysteresis. Simple friction uses the exact static threshold.
     source='\n'.join(['#include "model.h"','#include <math.h>','#include <string.h>',*declarations,
@@ -731,6 +737,7 @@ def compile_extended_program(network):
             num(sum(c.fstick*(1.001 if int(c.frictionType)==2 else 1) for c in dry))+'}'
             for group,dry,threshold in friction_groups) or '{0,0,0,0}')+'};',
         f'const NativeStop model_stops[{max(1,len(stops))}] = {{'+(','.join('{'+str(s[0])+','+','.join(num(v) for v in s[1:])+'}' for s in stops) or '{0,0,0,0,0,0,0}')+'};',
+        contact_source,
         'const double model_atol[NSTATES] = {'+','.join(map(state_absolute_tolerance, state_keys or ['dummy']))+'};',
         'const char *const model_output_keys[NOUTPUTS] = {'+(','.join(json.dumps(v.key,ensure_ascii=True) for v in variables) or '""')+'};',
         *jacobian.source_lines(),
@@ -774,6 +781,7 @@ int model_property_temperatures(double t,const double *y,NativePropertyTemperatu
 #define NOUTPUTS {max(1,len(variables))}
 #define NSTOPS {len(stops)}
 #define NFRICTIONS {len(friction_groups)}
+{contact_header}
 extern const NativeFriction model_frictions[{max(1,len(friction_groups))}];
 int model_friction_drives(double t,const double *y,double *drives);
 extern const NativeStop model_stops[{max(1,len(stops))}];