Fix vehicle corona/shadow flicker on fogless to foggy weather blend

[Zephkek]

Summary

Include CClock::ms_nGameClockSeconds in CWeatherSA::ResyncInterpolationWithGameClock so CWeather::InterpolationValue matches the value CWeather::Update derives (seconds/3600 + minutes/60).

Motivation

Follow-up to #4882. Residual flicker on vehicle coronas and shadows during fogless to foggy weather blends (e.g. SUNNY_COUNTRYSIDE to FOGGY_SF reported by rx).

The previous resync snapped InterpolationValue to minute/60 only. CTimeCycle::CalcColoursForPoint then blended m_CurrentColours between the weather pair using that snapped value, so:

• m_CurrentColours.m_fSpriteBrightness (read by CEntity::ProcessLightsForEntity at 0x6FCF83 for vehicle corona intensity)
• m_CurrentColours.m_wShadowStrength (read by CShadows::StoreShadowForVehicle at 0x70BDB9 for vehicle shadow intensity)

both updated in per-game-minute steps. With fast game clocks one game-minute is a fraction of a real second, so the steps surfaced as visible flicker on cars. CWeather::Foggyness itself was already smooth (it uses v0), which is why building lights and most other weather-driven values were fixed by #4882.

Adding seconds keeps the wrap-suppression intact (v0 >= InterpolationValue still holds, equal) and lets m_CurrentColours interpolate smoothly each frame.

Test plan

1. On a fast-clock server, set weather with setWeatherBlended from a fogless weather (e.g. 14 SUNNY_COUNTRYSIDE) to a foggy one (e.g. 9 FOGGY_SF).
2. Drive past a parked vehicle and watch its coronas and ground shadow during the blend hour.
3. Expected: brightness/shadow strength change smoothly, no per-tick flicker.
4. Confirm building lights, sky, and reflective surfaces from Fix #4803 building light flicker via pre-CWeather::Update hook  #4882 still behave correctly.

Checklist

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