renderer: Fix mirrored displays when transformed and preserve aspect ratio (#5697)

* renderer: transform mirror buffer and preserve mirror aspect ratio

* renderer: render mirrors directly from offloadFB

* renderer: fix formatting

* renderer: use monitorMirrorFB again, but properly damage mirrors

* renderer: clean mirrors after reload and support cursor zoom mirroring

src/config/ConfigManager.cpp

@@ -826,6 +826,10 @@ void CConfigManager::postConfigReload(const Hyprlang::CParseResult& result) {
 
         // Force the compositor to fully re-render all monitors
         m->forceFullFrames = 2;
+
+        // also force mirrors, as the aspect ratio could've changed
+        for (auto& mirror : m->mirrors)
+            mirror->forceFullFrames = 3;
     }
 
     // Reset no monitor reload