added land conversion methods

[jucordero]

Description

This PR introduces new model functions and LandDataArray accessor functions to facilitate models where land is converted between different categories.

• scale_land is a basic multitool to scale and shift land quantities between existing a new categories. It optionally allows total land to be conserved by scaling selected target categories.
• land_scaling_from_food performs land scaling based on the relative shifts between food quantities on selected Food Balance Sheet array elements and items. It uses scale_land.
• LandDataArray.add_category is an accessor method which allows the addition of new categories to LandDataArray, optionally providing fill values in the form of scalars or spatial and/or temporal arrays.

It also standardises the terminology by referring to the different land uses as "categories", avoiding the use of "type" and "class" which can be confused with standard Python terminology. Several functions using old terminology have been assigned deprecation warning and will be removed in the future releases of the package.

This PR fixes #91 and #92

Checklist

• Follow the Contributor Guidelines
• Write unit tests
• Write documentation strings

[Copilot]

Pull request overview

This PR introduces new land conversion/scaling utilities (including pipeline-compatible model nodes) and expands the LandDataArray accessor API to support adding land categories, while standardizing terminology from “type/class” to “category” with deprecation paths for older names.

Changes:

• Add new land intervention model functions: scale_land() and land_scaling_from_food().
• Add LandDataArray.add_category() and rename/accessor API terminology to “category” (with deprecation warnings for older method/kwarg names).
• Update and extend land accessor tests to use the new naming and to cover add_category() behavior.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 13 comments.

File	Description
agrifoodpy/land/land.py	Adds category-based APIs, deprecation shims, plotting kwarg rename, and new add_category() accessor.
agrifoodpy/land/model.py	Adds pipeline-node model functions for land conversion and FBS-driven land scaling; updates sequestration to use new category naming.
agrifoodpy/land/tests/test_land.py	Renames tests to “category” terminology and adds test coverage for add_category().

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.