cache open meteo api data & refactor the code

[samsatoshis]

adding cache to the open-meteo api data, the cached data covers the period from 1990-01-01, to 2024-12-08. If a request falls outside this date range, the system will fetch the data directly from open-meteo, otherwise, it will return the cached data.

[wherop]

Looks good. Sensible changes, clear logic.
On the long term, it could make sense to do some of the processing/aggregation before caching and store just one data point per day. But this works well for now.