fix: handle directory entries in install — rm -rf, ln -sfn

install.sh

@@ -21,12 +21,12 @@ while IFS= read -r rel || [ -n "$rel" ]; do
         mkdir -p "$BACKUP_DIR/$(dirname "$rel")"
         cp -a "$dest" "$BACKUP_DIR/$rel"
         echo "  Backed up: $dest"
-        rm -f "$dest"
+        if [ -d "$dest" ]; then rm -rf "$dest"; else rm -f "$dest"; fi
     elif [ -L "$dest" ]; then
         rm "$dest"
     fi
     [[ "$rel" == .ssh/* ]] && chmod 600 "$src" 2>/dev/null || true
-    ln -sf "$src" "$dest"
+    ln -sfn "$src" "$dest"
     echo "  Linked: ~/$rel"
 done < "$MANIFEST"