fix(codemod): preserve comment lines in metadata block

Comment lines (# ...) inside metadata blocks were being stripped
and their content parsed as field values. Now preserved verbatim.

Result: 275/289 deep equivalent

Author: ronaldtse

lib/interscript/isc/codemod.rb

@@ -209,6 +209,9 @@ def convert_metadata_block
           elsif @scanner.scan(/\}/)
             depth -= 1
             @out << "}"
+          elsif @scanner.scan(/\n[ \t]*#[^\n]*/)
+            # Comment line — preserve as-is
+            @out << @scanner.matched
           elsif @scanner.scan(/\n[ \t]*\n/)
             # Blank line — preserve one newline
             @out << "\n"