fix: add seedance 480p resolution option

[nblog]

Summary

• Add 480p to Seedance 2.0 T2V/I2V/R2V catalog resolution options.
• Regenerate backend and frontend model catalog artifacts.
• Map Seedance MuleRun CLI 480p requests to 832*480.

Test plan

• .venv/bin/python scripts/validate_model_catalog.py
• git diff --cached --check
• Frontend Vitest not rerun in this environment: WSL has no Linux Node, and Windows Node cannot load the Linux Rollup optional package from the existing node_modules.