fix: add api_key auth to SeedanceSaveVideo for video download

docs(04-01): add README, README_CN, and LICENSE for publishing

chore(04-01): rewrite .gitignore and remove tracked dev artifacts

docs(04-publish): create phase plan

docs(04): research publish phase domain

docs(state): record phase 4 context session

docs(04): capture phase context

docs(phase-03): evolve PROJECT.md after phase completion

docs(phase-03): complete phase execution

docs(03-02): complete omni reference plan

feat(03-02): add SeedanceOmniReference node with registration and tests

feat(03-02): add omni reference API client functions and tests

docs(03-01): complete video extend plan

feat(03-01): add SeedanceExtendVideo node with registration and tests

feat(03-01): add extend API client functions and tests