migrate-waniwani-sdk-0.19-to-0.20

Migrate a project from @waniwani/sdk 0.19.x to 0.20.x and auto-apply its breaking change: the entire legacy tier is deleted. The entry points @waniwani/sdk/legacy, /legacy/react, /legacy/next-js, /legacy/express-js, /next-js, /express-js and /chat/server no longer exist, ChatCard is gone from @waniwani/sdk/chat, and @modelcontextprotocol/ext-apps is no longer a peer dependency. Covers…