feat: add 'wenyan draft' subcommand (list/append/replace/update)

[dy2651]

Summary

Add a new wenyan draft subcommand for managing WeChat MP drafts. Supports both interactive and CLI modes.

List drafts

wenyan draft --list

Update title only

wenyan draft -u <mediaId> -t "New Title"

Append text to end

wenyan draft -u <mediaId> -a "text to append"

Search and replace

wenyan draft -u <mediaId> -s "old" -r "new"

Replace whole content with markdown file

wenyan draft -u <mediaId> -f article.md

Interactive mode (select draft + operation)

wenyan draft -i

Dependencies

Added @inquirer/select for interactive draft selection and operation picking.

Testing

All modes tested against a real WeChat MP account with 3 drafts.

[caol64]

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