2026/feat/process demand refactor

[daniel-rdt]

Refactors #808.

Changes proposed in this Pull Request

This PR proposes a couple of refactorings mentioned in #808.

• Makes use of the wildcard for the demand_type and gets rid of all of the individual rules. Instead introduces a global variable that maps the wildcard "nice name" to the file name prefix that we need for reading in that demand
• Renames weather_year to weather_scenario
• Moves the weather scenario option to the top level of the configuration
• Refactors the logic of selecting weather scenarios. Specifies the available weather scenarios also as a global variable AVAILABLE_WEATHER_SCENARIOS and in the config, the user is only selecting which ones they want modelled. We are now falling back to the list of available ones when we check if the configured ones are valid.

Tasks

Workflow

Open issues

Notes

Checklist

Required:

• Security scans show no high-severity bugs, critical vulnerabilities, or exposed secrets.
• Changes are tested locally and behave as expected.
• Code and workflow changes are documented.
• A release note entry is added to doc/release_notes.md.
• The description is human-written and any AI-generated content is marked.

If applicable:

• Changes in configuration options are reflected in scripts/lib/validation.
• Changes in configuration options are added to config/test/*.yaml.
• Multiple climate years test passes locally (pixi run -e open-tyndp tyndp-cyears-test).
• For new data sources or versions, these instructions have been followed.
• Open-TYNDP SPDX license header is added to all touched files.
• Module docstrings are added to new Python scripts.
• New rules are documented in the appropriate doc/*.md files.
• Major features are documented in doc/index.md.

[lisazeyen]

thanks @daniel-rdt for the suggestions! I will integrate your changes in the process demand PR.