fix(subscription): show expiry clock time (MSK) when under a day

- subscription_time_left: replace floor-div '23 ч.'/'мин.' branches with the
  concrete expiry timestamp when less than a full day remains
- add MSK_TIMEZONE (UTC+3) as display default; label time as '(МСК)'
- add shared subscription_status_text helper, use it in status menu,
  post-payment reply and dev confirmation instead of floor-rounded days
- tests: cover under-a-day clock format; fix stale to_thread mock

VERSION

@@ -1 +1 @@
-0.1.0+78
+0.1.0+79