Add ClipForge Local web studio

[iPythoning]

Summary

• Add a local-first Next.js web studio for marketing short-video generation
• Preserve existing OpenClaw skill workflow while adding Seedance 2.0 and Fish Audio adapter paths
• Add SQLite project storage, FFmpeg/Remotion rendering scaffolds, integration status API, tests, and setup docs

Verification

• npm run test
• npm run lint
• npm run build

Notes

• External API keys are documented in .env.example only; no real keys are committed
• Seedance/Fish are opt-in via API enhanced mode to avoid accidental quota usage