Fix rpm-ostree compatibility and postinst script issues

- Add --version and --help flags for rpm-ostree compatibility
- Fix postinst script to handle 'triggered' argument properly
- Maintain subcommand interface while adding flag support
- Improve error messages and help text

debian/apt-ostree.postinst

@@ -127,6 +127,23 @@ EOF
         echo "Aborting $PACKAGE configuration..."
         ;;
         
+    triggered)
+        # Handle trigger activation (e.g., man page updates, shell completion)
+        echo "Handling $PACKAGE triggers..."
+        
+        # Update shell completion caches
+        if command -v update-bash-completion >/dev/null 2>&1; then
+            update-bash-completion apt-ostree || true
+        fi
+        
+        # Update man page database
+        if command -v mandb >/dev/null 2>&1; then
+            mandb -q || true
+        fi
+        
+        echo "$PACKAGE triggers handled successfully"
+        ;;
+        
     *)
         echo "postinst called with unknown argument \`$1'" >&2
         exit 1