Implement PINT (Put IN one at a Time) CBA methodology

[cdgaete]

Closes #136.

Changes proposed in this Pull Request

Implements the PINT (Put IN one at a Time) methodology for Cost-Benefit Analysis as specified in TYNDP 2024 CBA guidelines.

New scripts:

• scripts/cba/prepare_pint_reference.py: Prepares the PINT reference network containing only in_reference=True projects
• scripts/cba/prepare_pint_project.py: Adds a single candidate project to the PINT reference network

Modified files:

• rules/cba.smk: Added hurdle_costs param to prepare_pint_project rule; updated input_indicators() to filter projects by CBA method
• scripts/cba/_helpers.py: Added filter_projects_by_method() with registry pattern for method-specific project filtering

Tasks

• Create PINT reference network script
• Create PINT project network script
• Add method-based project filtering (only in_reference=False for PINT)
• Update workflow rules

Workflow

To run PINT analysis, add pint to the cba.methods list in config:

cba:
  methods:
  - toot
  - pint

Open issues

None

Notes

• PINT and TOOT use the same downstream rules (solve_cba_network, make_indicators, collect_indicators, plot_indicators)
• Project filtering by in_reference status happens at workflow level in input_indicators() for consistency
• Registry pattern (METHOD_PROJECT_FILTERS) allows easy addition of future CBA methods

Checklist

• I tested my contribution locally and it works as intended.
• Code and workflow changes are sufficiently documented.
• Changed dependencies are added to pixi.toml (using pixi add <dependency-name>).
• Changes in configuration options are added in config/config.default.yaml.
• Changes in configuration options are documented in doc/configtables/*.csv.
• Changes in configuration options are added in config/test/*.yaml.
• Open-TYNDP SPDX license header added to all touched files.
• Sources of newly added data are documented in doc/data_sources.rst.
• New rules are documented in the appropriate doc/*.rst files.
• A release note doc/release_notes.rst is added.
• Major features are documented with up-to-date information in README and doc/index.rst.
• Module docstrings added to new Python scripts.