Pin DLL to prevent unload crash from libgsf DllMain

Use GetModuleHandleExW with GET_MODULE_HANDLE_EX_FLAG_PIN to prevent
the DLL from being unloaded during process exit. This stops libgsf's
DllMain(DETACH) from running and crashing when it tries to clean up
GLib objects that are in an inconsistent state during termination.

Also removes MsiCloseAllHandles from ProcessExit and removes the
MsiHandle finalizer - the OS reclaims all memory on exit.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: caesay

msi-interop/handle_table.c

@@ -316,6 +316,13 @@ __attribute__((constructor))
 static void
 handle_table_auto_init(void)
 {
+#ifdef _WIN32
+    // Pin this DLL so it's never unloaded. Prevents libgsf's DllMain from
+    // running during process exit, which crashes when GLib objects remain.
+    HMODULE hSelf;
+    GetModuleHandleExW(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_PIN,
+                       (LPCWSTR)handle_table_auto_init, &hSelf);
+#endif
     gsf_init();
     g_type_ensure(libmsi_database_get_type());
     g_type_ensure(libmsi_query_get_type());