Files
HealthLog/src/lib/tz
Marc-André Bombeck 68c67e4700 fix(fitbit): anchor offset-less sleep timestamps to the user timezone
The classic 1.2 sleep log and the activities list emit local wall-clock
ISO strings without an offset. `parseLocalInstant` parsed them with a bare
`new Date(iso)`, which reads an offset-less string in the process zone (UTC
in production). A non-UTC user's sleep-segment `measuredAt` (the segment
end) was therefore shifted by their UTC offset, and a near-midnight segment
could flip onto the wrong wake-day in the night reconstruction.

Resolve offset-less timestamps against the user's stored timezone via a new
`zonedWallClockToUtc` helper (the inverse of `wallClockInTz`, DST-safe via
the same two-pass converge as `startOfLocalDayInTz`). Thread the resolved
zone through the sleep and workout sync paths. Strings that already carry an
offset or `Z` stay absolute and parse as-is; an absent zone keeps the prior
host-local fallback.
2026-06-22 08:09:57 +02:00
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