scripts: warn when incoming commits touch Unity scene/asset files

scripts/session-git-check.sh

@@ -20,6 +20,14 @@ if git rev-parse --git-dir >/dev/null 2>&1; then
     if [ -n "$incoming" ]; then
       add "INCOMING commits on $upstream (you are behind — pull to get them):"
       while IFS= read -r l; do add "  $l"; done <<< "$incoming"
+      # Flag incoming edits to Unity scene/prefab/asset files — risky to pull
+      # while the Editor is open (it may overwrite them or hold a stale copy).
+      scenefiles=$(git diff --name-only "HEAD..$upstream" 2>/dev/null | grep -Ei '\.(unity|prefab|asset|mat|controller)$')
+      if [ -n "$scenefiles" ]; then
+        add "  *** WARNING: incoming commits change Unity scene/asset files:"
+        while IFS= read -r f; do add "      $f"; done <<< "$scenefiles"
+        add "  *** CLOSE or save the Unity Editor before pulling to avoid clobbering scene state."
+      fi
     else
       add "Up to date with $upstream (no incoming commits)."
     fi