Product design for assets-gen

[nighca]

Update #1455.

[qiniu-prow[bot]]

Skipping CI for Draft Pull Request. If you want CI signal for your change, please convert it to an actual PR. You can still manually trigger a test run with /test all

[xgopilot[bot]]

Code Review Summary

Excellent product documentation for the asset generation feature! The design is well-thought-out with clear technical concepts and good bilingual consistency. However, several critical security and clarity issues need attention before implementation.

Key Strengths:

• Clear differentiation from generic asset generation platforms
• Well-structured progression from features → concepts → risks
• Cost-conscious design with search-before-generate strategy
• Honest acknowledgment of technical challenges

Critical Issues Requiring Action:

1. Security (CRITICAL): Missing content moderation strategy for child safety in a platform designed for ~10-year-olds
2. Missing Definition: "Costume-group Animation" term used but never defined
3. Security: No rate limiting/abuse prevention details despite high video generation costs (¥1/sec)
4. Inconsistency: Formatting differences between English/Chinese versions (trailing "等")

See inline comments for specific recommendations.