Tighten inter-token merge specs

Assert parsed keys so the regression captures the merge contract without depending on raw output formatting.

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Generated with the help of Codex, https://openai.com/codex

Co-Authored-By: Codex GPT-5 <noreply@openai.com>

Author: mokagio

spec/ios_l10n_helper_spec.rb

@@ -138,10 +138,8 @@ def file_encoding(path)
         File.write(input_file, content)
         output_file = File.join(tmp_dir, 'output.strings')
         described_class.merge_strings(paths: { input_file => 'pfx.' }, output_path: output_file)
-        merged = File.read(output_file)
-        expect(merged).to include('"pfx.CFBundleName"')
-        expect(merged).to include('"pfx.AppName"')
-        expect(merged).to include('"pfx.DisplayName"')
+        merged_keys = described_class.read_strings_file_as_hash(path: output_file).keys
+        expect(merged_keys).to contain_exactly('pfx.CFBundleName', 'pfx.AppName', 'pfx.DisplayName')
       end
     end