Email copy grades

channel is email (default), linkedin_connection or linkedin_message; any other value is 400 on channel. Email sends the text to Jev using the client-system copy questions and returns those scores plus an overall band (keep, rewrite, start_over). Callers prefix a follow-up themselves. A LinkedIn step returns five 0-10 bars (quick_read, cta, easy, weird_word, personal), their mean as the score, keep at 7.5 or more with no weird_word alarm, rewrite at 5.5 or more, else start_over; a connection note over 300 characters fails easy. A saved grade for subjectKey and channel is returned even when the copy changed. refresh: true grades the new copy and replaces that row, and needs campaigns edit (403 otherwise). Requires campaigns view and Ask. Each call takes one unit of the workspace's aiEmailCopyGrades quota (20 a minute, 500 a day, every caller kind): past it, 429 quota_exceeded with Retry-After. campaignId is optional: a recruiting campaign of the workspace grades with the recruiting rubric and saves under its own key, so its subjectKey is at most 149 characters (129 on linkedin_connection, 132 on linkedin_message); another workspace's campaign is 404. A subjectKey cannot start with recruiting:.