refactor!: collapse three time-left format defcustoms into one alist

I merged `chime-time-left-format-at-event', `chime-time-left-format-short',
and `chime-time-left-format-long' into a single alist `chime-time-left-formats'
keyed by `at-event' / `short' / `long'. Three knobs for one feature
(countdown display) was unnecessary surface area; one alist is the same
flexibility with a third the namespace.

`chime--time-left' switched from a pcase-on-variable to a pcase-on-regime
that picks an alist key, then `alist-get's the format string. Behavior
is identical for default settings.

Test setup in the four affected files now builds the alist with `(list
(cons 'KEY VAL) ...)' instead of `'(...)'. The literal-quote form
returns the SAME cons-cell structure on every evaluation, so a previous
test mutating it via `setf' on `alist-get' poisoned later tests. `list'
+ `cons' produces fresh structure per call, which is what the tests
actually need.

Migration: `(setq chime-time-left-format-short "in %mm")' becomes
`(setf (alist-get 'short chime-time-left-formats) "in %mm")', or a
full `(setq chime-time-left-formats '((at-event . ...) (short . ...)
(long . ...)))' replacement.

0 files changed, 0 insertions, 0 deletions