fix: normalize schedule date_utc to ISO 8601 with Z suffix for correct browser timezone conversion

[Clav3rbot]

Problem

The \date_utc\ values in the static schedule JSON files (e.g. \data/seasons/2026/schedule.json) use the format \2026-03-15 07:00:00\ without a timezone indicator. When the frontend receives these values, JavaScript's
ew Date('2026-03-15 07:00:00')\ treats them as local time instead of UTC, so users see raw UTC times instead of their local timezone.

Fix

Normalize \date_utc\ strings in _build_events()\ before returning the response:

• Replace space separator with \T\ (ISO 8601)
• Append \Z\ suffix to indicate UTC

This ensures the frontend's \FormatLocalTime()\ function correctly interprets dates as UTC and converts them to the user's local timezone via \ oLocaleTimeString().

Example

• Before: \2026-03-15 07:00:00\ → browser shows 7:00 AM (wrong, treated as local time)
• After: \2026-03-15T07:00:00Z\ → browser shows 8:00 AM CET (correct UTC→local conversion)