chore: update flakebox files

misc/git-hooks/pre-commit

@@ -132,8 +132,13 @@ export -f check_trailing_newline
 function check_trailing_whitespace() {
     set -euo pipefail
 
-    if ! git diff --check HEAD ; then
-      echo "Trailing whitespace detected. Please remove them before committing."
+    rev="HEAD"
+    if ! git rev-parse -q 1>/dev/null HEAD 2>/dev/null ; then
+      >&2 echo "Warning: no commits yet, checking against --root"
+      rev="--root"
+    fi
+    if ! git diff --check $rev ; then
+      >&2 echo "Trailing whitespace detected. Please remove them before committing."
       return 1
     fi