This commit introduces memoization to various methods in the Planting model,
PredictPlanting and PredictHarvest concerns, PlantingsHelper, and
PlantingsController.
Specifically:
- Memoized database-intensive lookups like `nearby_same_crop`, `first_harvest_date`,
and `last_harvest_date`.
- Memoized calculated fields like `finish_predicted_at`, `expected_lifespan`,
and `age_in_days`.
- Optimized `PlantingsHelper#transplantable_gardens_by_owner` using a hash
to cache results per planting instance within a request.
- Applied the `defined?(@variable)` pattern where appropriate to ensure
efficient handling of `nil` results.
These changes reduce redundant database queries and expensive calculations,
particularly during view rendering where these methods are frequently accessed.
Co-authored-by: CloCkWeRX <365751+CloCkWeRX@users.noreply.github.com>