fix 5.2 audit findings on Windows: F-PROC-1 injection, F-MEM-5 UAF, F-PROC-2 restart race, F-PROC-3, F5, F6

native_bridge/src/NativeInstrumentEngine.cpp

@@ -303,6 +303,11 @@ INativeInstrument* InstrumentEngineManager::get(uint32_t channel) {
     return it == channels_.end() ? nullptr : it->second.get();
 }
 
+bool InstrumentEngineManager::has(uint32_t channel) {
+    std::lock_guard<std::mutex> lock(mu_);
+    return channels_.count(channel) != 0;
+}
+
 void InstrumentEngineManager::setReloading(uint32_t channel, bool on) {
     std::lock_guard<std::mutex> lock(mu_);
     if (channel < 16) reloadingCh_[channel] = on;