[Bug] Incorrect time zone offset for Novosibirsk (GMT+6 instead of GMT+7)

Your system information

• Steam client version: 1782861641
• SteamOS version: 3.8.14
• Opted into Steam client beta?: No
• Opted into SteamOS beta?: No
• Have you checked for updates in Settings > System?: Yes (System is up to date)

Please describe your issue in as much detail as possible:

When configuring the time zone on Steam Deck for "Novosibirsk", the system applies the incorrect UTC offset.

Expected behavior:

Novosibirsk should be set to GMT+7 (OMST).

Actual behavior:

The system incorrectly associates Novosibirsk with the "North Central Asia Standard Time" (GMT+6), which is usually associated with regions like Almaty. In reality, Novosibirsk belongs to the "North Asia Standard Time" (GMT+7) zone, which currently covers regions like Krasnoyarsk. As a result, the system clock is one hour behind the actual local time in Novosibirsk.

Steps for reproducing this issue:

1. Go to Settings > Date & Time.
2. Select Time Zone (or set it manually if automatic detection is off).
3. Navigate to Asia region.
4. Select Novosibirsk.
5. Observe the system time displayed on the top bar; it will show the incorrect GMT+6 time instead of the correct GMT+7 time.

Start by reproducing the issue through Settings > Date & Time, selecting Asia > Novosibirsk, and verifying the displayed offset. Trace the timezone mapping used by SteamOS for Novosibirsk and confirm the fix by checking that it reports GMT+7 (OMST) rather than GMT+6.