more CoPilot fixes for help html gen workflow

Author: briantoby

.github/workflows/update_help.yml

@@ -47,10 +47,10 @@ jobs:
             files_changed="false"
           else
             # Get the most recent commit date for .md files in docs directory
-            docs_latest=$(cd _docs && find MDhelp/docs -name "*.md" -type f | xargs git log -1 --format=%cI -- 2>/dev/null | sort -r | head -1)
+            docs_latest=$(cd _docs && git ls-tree --name-only -r HEAD -- MDhelp/docs | grep '\.md$' | while read filename; do echo "$(git log -1 --format="%ai" -- "$filename") $filename"; done | sort -r | head -1 | cut -d' ' -f1-3)
             
             # Get the most recent commit date for the help directory
-            help_latest=$(git log -1 --format=%cI -- "GSASII/help/" 2>/dev/null || echo "")
+            help_latest=$(git ls-tree --name-only -r HEAD -- GSASII/help | while read filename; do echo "$(git log -1 --format="%ai" -- "$filename") $filename"; done | sort -r | head -1 | cut -d' ' -f1-3)
             
             if [ -z "$docs_latest" ]; then
               echo "Could not get commit date for markdown files in docs directory"
@@ -59,8 +59,11 @@ jobs:
               echo "help directory has no commit history, will build"
               files_changed="true"
             else
-              # Compare ISO 8601 dates (they sort correctly as strings)
-              if [ "$docs_latest" > "$help_latest" ]; then
+              # Convert dates to epoch seconds for reliable numeric comparison
+              docs_epoch=$(date -d "$docs_latest" +%s 2>/dev/null || echo 0)
+              help_epoch=$(date -d "$help_latest" +%s 2>/dev/null || echo 0)
+              
+              if [ "$docs_epoch" -gt "$help_epoch" ]; then
                 echo "Markdown docs are newer (docs: $docs_latest, help: $help_latest)"
                 files_changed="true"
               else