utilities as time series

Handle time series data input for utilities such that we can insert time dependent production and cost profiles.

Implement a cashflow model which will calculate an approximate NPV based on production profiles, prices and cost profiles (profiles → time series per year)

This would include an interface to retrieve and add production profiles, prices and cost profiles.

Some of the data like production profiles could be retrieved from Equinor internal APIs.
- time-dependent variables
- parser for mathematical operations
- visualization of time-dependent variables

No files, tests, or entry points are named. Start by locating the existing utilities API and data models, then map the requested time-series production, price, and cost profiles to the cashflow and NPV requirements. Done should cover profile retrieval and insertion, time-dependent operations, and visualization as described.

Written by the indexing model from the issue text.