Fix duplicate Carbon Code zh-CN guidance

[w287346141]

Summary

• fix a zh-CN workspace conflict warning that said Carbon Code Code
• add regression coverage so the duplicated brand wording does not come back

Verification

• npm.cmd run test -- carbon-productization.test.ts
• npm.cmd run typecheck
• npm.cmd run verify
• manual: Select-String for Carbon Code Code returns no matches

[w287346141]

Superseded by #20, which batches this zh-CN branding fix together with #17 and resolves the shared tests/carbon-productization.test.ts conflict ahead of review.