added-env-based-history-window

[ajey35]

Pull Request

Description

This PR introduces a configurable history window for the Quartz Frontend via environment variables.
It allows developers to control how far back in time the UI fetches solar forecast and actual data — without changing code manually.

Previously, the application used a fixed time window (e.g., 48 hours).
Now, this can be configured using environment variables such as:

NEXT_PUBLIC_HISTORY_WINDOW_TYPE=fixed|rolling
NEXT_PUBLIC_HISTORY_WINDOW_HOURS=48|72

Fixes #655 — Set start of window for UI for all forecast/actuals

How Has This Been Tested?

Ran the application locally using different environment variable settings:

NEXT_PUBLIC_HISTORY_WINDOW_TYPE=fixed
NEXT_PUBLIC_HISTORY_WINDOW_TYPE=rolling

Verified that the API requests (to /v0/solar/GB/gsp/pvlive/all and /v0/solar/GB/national/forecast) reflected correct start_datetime_utc and end_datetime_utc parameters.
Confirmed that the charts updated accordingly for both 48-hour and 72-hour modes.
Ran yarn lint and yarn test successfully after correcting formatting issues.

Checklist

• My code follows OCF's coding style guidelines
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• I have checked my code and corrected any misspellings

[vercel]

@ajey35 is attempting to deploy a commit to the Open Climate Fix Team on Vercel.

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