feat(wan): add Tongyi Wansiang CLI synced from Docs openapi/wan.json

[Copilot]

Docs updated openapi/wan.json (Tongyi Wansiang video generation); no wan/ CLI existed in this monorepo. This PR creates it from scratch, fully aligned with the spec.

New: wan/ CLI package

• Package: wan-cli / entry points wan and wan-cli
• Endpoints covered:
  • POST /wan/videos → generate (text2video), image-to-video, reference-to-video
  • POST /wan/tasks → task (retrieve), tasks (retrieve_batch), wait (polling)
• Models: wan2.6-t2v (default), wan2.6-i2v, wan2.6-i2v-flash, wan2.6-r2v
• Parameters: resolution (480P/720P/1080P), duration (5/10/15s), shot_type (single/multi), negative_prompt, audio, prompt_extend, audio_url, reference_video_urls, image_url, callback_url
• Info commands: models, resolutions, shot-types, config

wan generate "Astronauts shuttle from space to volcano" -m wan2.6-t2v -r 720P -d 10
wan image-to-video "Animate this" -i https://cdn.acedata.cloud/r9vsv9.png
wan reference-to-video "A person dancing" --reference-video-urls https://example.com/ref.mp4
wan wait <task_id> --interval 10

Supporting changes

• sync.yaml: added wan → AceDataCloud/WanCli mapping
• Tests: 55 unit tests covering client, config, commands, and output modules