Mail · Sorting: a label picker and a snooze menu

LabelPicker puts labels on a message: a field finds them by name,
arrows move and a press or Enter turns one on or off, each row with its
check and its hue. A name no label has can be made into one, and the
field starts over. Its rows are the option rows every list shares;
forms::marked_row leads one with a mark. The cursor shows only while
the field has focus.

SnoozePicker offers later today, tomorrow, this weekend and next week,
each with its day and hour, or a time picked in a dialog. It shares
mail::times with ScheduleSend: the names, the dialog, which now waits
for a time ahead of now, and a rule that a moment comes once, so on a
Sunday tomorrow morning no longer repeats as Monday morning.

TASKS.md

@@ -105,7 +105,7 @@ Per-component lines live in `tasks/`. Tags there:
 - [x] T28e Messaging · Stickers and GIFs
 - [x] T29a Mail · Boxes and lists
 - [x] T29b Mail · Reading
-- [ ] T29c Mail · Writing
+- [x] T29c Mail · Writing
 - [ ] T29d Mail · Sorting
 - [ ] T30 Calendar
 - [ ] T31 Project — `tasks/ch31-43.md`
@@ -346,3 +346,5 @@ Per-component lines live in `tasks/`. Tags there:
 | T29a | 2 | PASS | |
 | T29b | 1 | FAIL | a folded message lost focus as it opened; a long name beside a long date ran past a 280px fold |
 | T29b | 2 | PASS | |
+| T29c | 1 | FAIL | a long chip ran past its tag field at 280px |
+| T29c | 2 | PASS | |