Posts may be submitted with longer content than supplied. We should let the client know when a post was truncated so they can notify the user / handle it more gracefully.
Without this, we're deleting users' content without any recourse for them. This is bad, and goes against the "no data loss" principle of Write.as.
New idea for Write.as and WriteFreely: add an endpoint that returns whether or not a post will be truncated, so new clients can handle this situation correctly (like by notifying the user). In the web editor, warn the user before publishing if a post will be truncated, and allow them to continue publishing anyway or cancel. On our existing publishing endpoint, just return truncated: true if the post was truncated.
Old implementation idea:
If a post is created and must be truncated due to a user's subscription level, save the full text to the database (within a reasonable limit, i.e. highest plan's limit) but return the truncated content and a truncated: true property.