The encode catch comment promised 'fall back to raw' but the code returns '';
returning raw source wouldn't help anyway (un-encoded markup can't be atob-decoded
downstream, so decode would yield '' regardless), and a raw value in data-source
breaks the inert-storage guarantee. '' is the correct decode-symmetric failure —
fix the misleading comment to say so. Adds a codec test for the encode-throw path.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
afbc6b2202