debug: add logging to build-deb to diagnose CI failure

run

@@ -91,11 +91,23 @@ function build-deb {
 
   # Set up environment
   dev-env
+  echo "DEBUG: dev-env completed"
 
   # Check if changelog was already generated by CI (shared-workflows)
   # If debian/changelog exists and was modified in the last 5 minutes, skip regeneration
+  echo "DEBUG: Checking debian/changelog..."
+  echo "DEBUG: PWD=$(pwd)"
+  echo "DEBUG: ls -la debian/changelog: $(ls -la debian/changelog 2>&1 || echo 'file not found')"
+
   if [ -f "debian/changelog" ]; then
-    CHANGELOG_AGE=$(($(date +%s) - $(stat -c %Y debian/changelog 2>/dev/null || stat -f %m debian/changelog)))
+    echo "DEBUG: debian/changelog exists, checking age..."
+    # Use stat -c for Linux, stat -f for macOS, handle errors gracefully
+    CHANGELOG_MTIME=$(stat -c %Y debian/changelog 2>/dev/null) || CHANGELOG_MTIME=$(stat -f %m debian/changelog 2>/dev/null) || CHANGELOG_MTIME=0
+    echo "DEBUG: CHANGELOG_MTIME=$CHANGELOG_MTIME"
+    CURRENT_TIME=$(date +%s)
+    echo "DEBUG: CURRENT_TIME=$CURRENT_TIME"
+    CHANGELOG_AGE=$((CURRENT_TIME - CHANGELOG_MTIME))
+    echo "DEBUG: CHANGELOG_AGE=$CHANGELOG_AGE"
     if [ "$CHANGELOG_AGE" -lt 300 ]; then
       echo "📋 Using existing debian/changelog (generated by CI)"
     else
@@ -110,8 +122,11 @@ function build-deb {
           --force-distribution \
           "Automated release $PACKAGE_VERSION. See GitHub for details."
     fi
+  else
+    echo "DEBUG: debian/changelog does not exist"
   fi
 
+  echo "DEBUG: About to run dpkg-buildpackage..."
   dpkg-buildpackage -us -uc -b
 
   echo "✅ Debian package built successfully"