Function getTransitPhase

getTransitPhase(
    transitLongitude: number,
    natalLongitude: number,
    transitSpeed: number,
    aspectAngle: number,
    deviation: number,
    exactThreshold?: number,
): TransitPhase
Determine the phase of a transit (applying, exact, or separating).
Parameters
- transitLongitude: number
  Current longitude of transiting body
- natalLongitude: number
  Longitude of natal point
- transitSpeed: number
  Daily motion of transiting body (degrees/day)
- aspectAngle: number
  The exact aspect angle (0, 60, 90, 120, 180)
- deviation: number
  Current deviation from exact aspect
- exactThreshold: number = DEFAULT_EXACT_THRESHOLD
  Threshold for marking as 'exact'
Returns TransitPhase
Transit phase
Remarks
- Applying: The aspect is forming (deviation is decreasing)
- Exact: The aspect is at or very near exact
- Separating: The aspect is waning (deviation is increasing)
The determination depends on:
1. Whether the planet is direct or retrograde
2. Whether the current separation is less than or greater than the aspect angle
- Defined in transits/transit-detection.ts:182