Update docs forecast

[lambaaryan011]

Pull Request

Description

This PR implements and documents the "day ahead" forecast rule across the India API. The changes ensure that forecasts adhere to the timing requirement that they must be generated before 9:00 IST on the day before the forecast date.

Key changes include:

      ⇾ Added forecast timing validation logic to enforce the rule

      ⇾Updated API documentation to clearly explain the timing requirements

      ⇾Added error handling for requests that don't meet the timing requirement

      ⇾Updated utility functions to respect the forecast timing rule

These changes standardize the forecast behavior and provide users with clear information about when forecasts are available.

Fixes #64

How Has This Been Tested?

→Simulating forecast requests at various times relative to the 9:00 IST cutoff

→Verifying that requests before cutoff time return appropriate error messages

→Confirming that valid requests after cutoff time proceed normally

→Testing timezone handling across IST/UTC conversions

• Yes

If your changes affect data processing, have you plotted any changes? i.e. have you done a quick sanity check?

• Yes

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