Fix Worker.cpp namespace and function declaration

- Add proper xmrig namespace for setThrottlingState function
- Fix global variable declarations
- This should resolve linking errors from previous build

src/backend/common/Worker.cpp

@@ -30,7 +30,7 @@
 static bool g_isThrottled = false;
 static uint64_t g_originalAffinity = 0;
 
-extern "C" {
+namespace xmrig {
     void setThrottlingState(bool throttled, uint64_t originalAffinity) {
         g_isThrottled = throttled;
         g_originalAffinity = originalAffinity;