Ignore local logs, training data, and build/runtime artifacts

.gitignore

@@ -21,4 +21,21 @@ out/
 
 # --- OS Junk ---
 .DS_Store
-Thumbs.db
+Thumbs.db
+
+# --- Local Build / Runtime Artifacts (keep local, do not commit) ---
+CMakeCache.txt
+CMakeFiles/
+cmake-build-*/
+editor/build-native/
+build-native/
+
+# Runtime/editor local state
+imgui.ini
+.whetstone.json
+crash.log
+SDL-issue.log
+
+# Large/generated run data
+logs/
+training_data/