Write replays next to the executable

Place the "replays" folder in the executable's real directory
(QCoreApplication::applicationDirPath()) instead of traversing up from the
config dir with cdUp(). Relative traversal resolves incorrectly under a
symlinked build layout (landing in bin rather than the build tree); using the
exe's actual location avoids that. configDir is still passed for the config hash.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DUsFgd2Ga6pmLz8giS8WUn

src/ui/GameWorldView.cpp

@@ -10,6 +10,7 @@
 #include <string>
 
 #include <QColor>
+#include <QCoreApplication>
 #include <QCursor>
 #include <QDir>
 #include <QFont>
@@ -162,13 +163,15 @@ GameWorldView::GameWorldView(Simulation* sim, const GameConfig* config,
     }
     else
     {
-        // Record every run to disk. Replays live under <data>/replays, alongside
-        // the config dir that was loaded. Attaching the recorder opens the first
-        // file and writes the header for the initial run.
-        QDir replayDir(QString::fromStdString(configDir));
-        replayDir.cdUp();
+        // Record every run to disk, into a "replays" folder next to the executable.
+        // Uses the exe's real directory rather than traversing up from the config
+        // dir: with a symlinked build layout, relative traversal would resolve into
+        // the wrong tree. Attaching the recorder opens the first file and writes the
+        // header for the initial run.
+        const QString replayDir =
+            QDir(QCoreApplication::applicationDirPath()).filePath("replays");
         m_commandManager.setRecorder(std::make_unique<ReplayRecorder>(
-            configDir, replayDir.filePath("replays").toStdString()));
+            configDir, replayDir.toStdString()));
     }
 }