End an own draft at a line of one of its parts, or move some of its parts, and start a second entry

The body carries exactly one of at and leaving, else a 400. at lies strictly inside one of the entry's parts and on the grid at that point (D-219): a stored interval's edge of the author's day, or a line of the day's unit (the firm's when the day opened, or now for a day not opened yet) where none is stored, and never inside a stored interval (the stored intervals are those of the device the entry was generated on (its device_id), or, for a hand-made entry and one generated on the asking device, those of the device X-Six-Minute-Device names and the earlier ids X-Six-Minute-Device-Known names; with no device of the caller's named, every device's for a hand-made entry); anything else is a 422 on at naming the lines that exist. The first half KEEPS THE ID and holds the parts before at and the cut part up to it; the second is a new entry_ id holding the rest from at. leaving names parts of the entry, each exactly as it holds them, that become the second entry (a split at a gap, or one part detached from anywhere in the set); it is a strict, non-empty subset of the parts, else a 422 on leaving, and the rest keep the id. The second half has the same matter, day, zone, author, narrative, attributes, note and judged copy. Each half's t_start and t_end are its first start and last end, its recorded time is the sum of its parts, and neither keeps an override_seconds. The split writes the rows only: the intervals stay where they are, and each half covers the ones whose start lies in one of its parts (D-216). first and second are the narratives and attribute maps the person approved on the review before this call: both or neither, and each map REPLACES the half's attributes rather than merging into them; a half's optional matter_id moves that half as a PATCH does, and null moves it to no matter. Without them the parent's narrative and attributes are copied onto both halves, which is what a firm on the confidential tier gets, because it stores no judged text to propose from. A half's narrative longer than the firm's length (narrative.max_chars, else 240) is a 422 at first.narrative or second.narrative, and nothing is written (D-230). Both halves are stamped edited_at: a split is a person's edit, so the engine never replaces either of them again (Row E). It is the complement of the cut and not a correction to it; D-85's Split, which moves hours to another matter, is a different gesture and stays. A draft whose release is with the practice system, or for which the practice system holds or may hold a line from a release that did not finish, is a 409 (the latter on connector.pending: releasing the entry settles it).