Weather update: sandstorms and three intensity levels

Vanilla now rolls 10% rain, 10% sand, 80% clear for each map seed. Rain and sand are separate outcomes, never simultaneous. Both choose light/moderate/strong with equal probability. Continue keeps the event and level; it does not reroll. The previous version's saves retain rain or clear weather at moderate intensity.

This addendum is a new file so existing installations receive it without overwriting their weather guide or any edited mods. The current complete guide is WEATHER.md in the game's shipped mods_example folder.

To try sand, copy _example_sandstorm to desert_sandstorm in the folder opened by Options → Mods → Open Mods Folder. Disable any guaranteed-rain mod, restart and start a new game. Dust fades in over eight seconds; the example storm lasts two minutes with a random intensity. Rename its mod ID before sharing.

Use these new keys under weather in your mod's balance.json:

{
  "weather": {
    "rain_chance": 0.1,
    "sand_chance": 0.1,
    "intensity_weights": [1, 1, 1],
    "intensity_multipliers": [0.55, 1.0, 1.5],
    "sand_duration_seconds": [40, 85],
    "sand_density": 1.0,
    "sand_haze": 0.38,
    "sand_wind_multiplier": 2.4
  }
}

• sand_chance: 0–1. Rain has priority if the two probabilities exceed 1.
• intensity_weights: [light, moderate, strong], each 0–100. For example, [0,0,1] always chooses strong. All-zero/invalid arrays use equal weights.
• intensity_multipliers: strength of each level, bounded to 0.25–2. The chosen value scales rain/dust particles and wind. Keep increasing values for levels that grow in strength. This is independent of Low/Medium/High/Ultra quality.
• sand_duration_seconds: [min,max], each 5–1800 seconds. The existing start_delay_seconds and fade_seconds apply to both rain and sand.
• sand_density: particle multiplier, 0.1–2. Moderate-intensity base counts are 100/180/300/450 on Low/Medium/High/Ultra, including dust ribbons and grains.
• sand_haze: haze opacity per intensity multiplier, 0–0.6, capped at 0.72.
• sand_wind_multiplier: 0.5–4, multiplying the existing base wind and gusts.

Sand never creates water or lightning, and does not change combat or pathfinding. It uses ordinary depth fog and CPU particles in the shared 3D world. Both stop with pause; haze respects night lighting and clears when the storm ends or the world is reused. Rain keeps its reflective pools and night lightning, with particle density, wind, cloud cover and wetness responding to the chosen level.