Settings gains a Usage Refresh picker mirroring the quota cadence
pattern. Auto keeps the adaptive default (30s active, battery and Low
Power backoff); fixed cadences ignore power state but an open popover
always gets the active 30s; Manual never auto-spawns, refreshing only
on popover open, Refresh Now, and first launch (wake included: manual
wakes run stuck-state cleanup without spawning). Stored in UserDefaults
as CodeBurnMenubarRefreshSeconds (-1 auto, 0 manual, else seconds) and
documented in the README with the defaults-write escape hatch.
Refs #647
Every 30s tick spawned 2-3 concurrent Node CLI processes at 100%+ CPU,
and an app-lifetime activity assertion disabled App Nap forever, putting
the menubar's energy use in the video-call class (#647).
- Closed popover now fetches only what the status item renders (menubar
period plus today); the popover's selected key refreshes on open via
the existing recovery path, which now also catches up the status
figure and clears a latched display-sleep flag.
- Spawn cadence stretches to 150s on battery and 300s in Low Power Mode
while the popover is closed; the 30s timer itself keeps running.
- The app-lifetime beginActivity is gone; each in-flight refresh
(including manual Refresh Now) holds its own scoped activity, and an
NSBackgroundActivityScheduler backstop tick every ~3min bounds status
staleness once App Nap starts coalescing the timer.
- Display sleep skips ticks entirely; wake and popover open clear it.
- The status-payload fallback honors the same spawn interval so the 30s
cache TTL cannot defeat the backoff.
Child process QoS stays .userInitiated on purpose: lowering it is
documented to slow parses 5-10x and starve the cadence; the win here is
spawn frequency, not priority. Measured on an idle machine: two
concurrent 100%+ CPU spawns per 30s window before, one spawn in 72s
after, with App Nap coalescing the rest.
Fixes#647
