Hopefully fix fog light flicker precision (#4906)

#### Summary
Adjust weather interpolation resync precision in
`CWeatherSA::ResyncInterpolationWithGameClock`.
This keeps `InterpolationValue` aligned with the engine comparison path
and removes fog transition light flicker.

#### Motivation
Fog to sunny flicker was fixed, but lights still flickered when blending
into fog.
This change prevents precision mismatches that can trigger the wrap
branch and spike light related weather values.

#### Test plan
Test in-game on v26595 with fast clock and repeated `setWeatherBlended`
into fog.
Verify car lights, traffic lights, and other 2dfx lights no longer flash
each second during the blend.

Author: Zephkek

Client/game_sa/CWeatherSA.cpp

@@ -37,13 +37,16 @@ void CWeatherSA::ResyncInterpolationWithGameClock(unsigned char primary, unsigne
     else
     {
         // Match the value CWeather::Update derives at 0x72B897:
-        //   v0 = (seconds / 60 + minutes) / 60
-        // Snapping to minutes only would drop seconds and make CTimeCycle::CalcColoursForPoint
-        // step m_CurrentColours per game-minute, which surfaces as flicker on vehicle coronas
-        // (m_fSpriteBrightness) and shadows (m_wShadowStrength) when the clock runs fast.
-        const auto  ucMinute = *reinterpret_cast<unsigned char*>(VAR_TimeMinutes);
-        const auto  ucSecond = *reinterpret_cast<unsigned char*>(VAR_TimeSeconds);
-        const float fInterp = std::min(1.f, static_cast<float>(ucMinute) / 60.f + static_cast<float>(ucSecond) / 3600.f);
+        //   v0 = ((double)seconds * 0.016666668 + (double)minutes) * 0.016666668
+        // Keep this <= engine v0 to avoid triggering the wrap branch on precision mismatches.
+        const auto   ucMinute = *reinterpret_cast<unsigned char*>(VAR_TimeMinutes);
+        const auto   ucSecond = *reinterpret_cast<unsigned char*>(VAR_TimeSeconds);
+        const double dInterp = std::min(1.0, (static_cast<double>(ucSecond) * 0.016666668 + static_cast<double>(ucMinute)) * 0.016666668);
+        float        fInterp = static_cast<float>(dInterp);
+
+        if (static_cast<double>(fInterp) > dInterp)
+            fInterp = std::nextafterf(fInterp, 0.0f);
+
         MemPutFast<float>(VAR_InterpolationValue, fInterp);
     }
 }