feat: add ColumnType as_str method and improve error handling

src/modes/common.rs

@@ -59,6 +59,22 @@ pub enum ColumnType {
     Meta,
 }
 
+impl ColumnType {
+    /// Returns the human-readable string representation of the column type
+    pub fn as_str(&self) -> &str {
+        match self {
+            ColumnType::Id => "id",
+            ColumnType::Time => "time",
+            ColumnType::Size => "size",
+            ColumnType::Compression => "compression",
+            ColumnType::FileSize => "filesize",
+            ColumnType::FilePath => "filepath",
+            ColumnType::Tags => "tags",
+            ColumnType::Meta => "meta",
+        }
+    }
+}
+
 pub fn get_format_box_chars_no_border_line_separator() -> TableFormat {
     prettytable::format::FormatBuilder::new()
         .column_separator('│')