Function normalizeLatitude

normalizeLatitude(lat: number): number
Normalize latitude to valid range (-90 to +90)

Latitudes beyond ±90 are folded back into the valid range with appropriate hemisphere flipping.
Parameters
- lat: number
  Input latitude in degrees
Returns number
Normalized latitude in range [-90, +90]
Example
```
normalizeLatitude(45.5)     // 45.5 (already valid)
normalizeLatitude(95)       // 85 (folded back)
normalizeLatitude(-95)      // -85 (folded back)
normalizeLatitude(180)      // 0 (complete fold)
```
- Defined in houses/validation.ts:28