fix: avoid loader-lock work in DllMain detach

src/Utils/FileWatcher.h

@@ -4,7 +4,7 @@
 #include <string>
 #include <vector>
 
-namespace FileWatcher {
-    void Start(const std::vector<std::string>& directories);
-    void Stop();
-}
+namespace FileWatcher {
+    void Start(const std::vector<std::string>& directories);
+    void Stop();
+}

src/dllmain.cpp

@@ -74,22 +74,30 @@ static DWORD WINAPI InitThread(LPVOID param) {
     return 0;
 }
 
-BOOL APIENTRY DllMain(HMODULE hModule, DWORD dwReason, PVOID pvReserved)
-{
-    if (dwReason == DLL_PROCESS_ATTACH)
-    {
-        DisableThreadLibraryCalls(hModule);
-        // Hand off all real work to a worker thread to avoid running file I/O,
-        // LoadLibrary, and detour transactions under the loader lock.
-        HANDLE h = CreateThread(nullptr, 0, InitThread, hModule, 0, nullptr);
-        if (h) CloseHandle(h);
-    }
-    else if (dwReason == DLL_PROCESS_DETACH)
-    {
-        FileWatcher::Stop();
-        SteamUI::CoreUnhook();
-        SteamClient::CoreUnhook();
-    }
-
-    return TRUE;
-}
+BOOL APIENTRY DllMain(HMODULE hModule, DWORD dwReason, PVOID pvReserved)
+{
+    if (dwReason == DLL_PROCESS_ATTACH)
+    {
+        DisableThreadLibraryCalls(hModule);
+        // Keep this module pinned so explicit FreeLibrary cannot unload code
+        // while hooks and worker threads may still reference it.
+        HMODULE pinnedModule = nullptr;
+        GetModuleHandleExA(
+            GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_PIN,
+            reinterpret_cast<LPCSTR>(&DllMain), &pinnedModule);
+        // Hand off all real work to a worker thread to avoid running file I/O,
+        // LoadLibrary, and detour transactions under the loader lock.
+        HANDLE h = CreateThread(nullptr, 0, InitThread, hModule, 0, nullptr);
+        if (h) CloseHandle(h);
+    }
+    else if (dwReason == DLL_PROCESS_DETACH)
+    {
+        // During process termination, join watcher thread object so CRT static
+        // teardown does not hit std::thread's joinable-guard terminate.
+        if (pvReserved != nullptr) {
+            FileWatcher::Stop();
+        }
+    }
+
+    return TRUE;
+}