Add coverage simulations for repeated cross sections over multiple periods

[SvenKlaassen]

• Added DIDCSMultiCoverageSimulation to montecover
• Updated did section with corresponding qmd file
• minor fixes

[Copilot]

Pull Request Overview

This PR adds a new cross-sectional DiD simulation (DIDCSMultiCoverageSimulation) spanning multiple periods, integrates its results and config into the repository, and updates documentation and CI workflows to support it.

• Introduce DIDCSMultiCoverageSimulation class and export in montecover.did
• Add new result files, config, and metadata for the cross-sectional multi-period simulation
• Update documentation (.qmd) and CI (did_sim.yml) to include the new simulation

Reviewed Changes

Copilot reviewed 28 out of 28 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
monte-cover/src/montecover/did/did_cs_multi.py	New simulation class for cross-sectional multi-period coverage
monte-cover/src/montecover/did/init.py	Exported the new DIDCSMultiCoverageSimulation
results/did/did_cs_multi_*.csv & .yml	Added new result, metadata, and config files
doc/did/did_cs_multi.qmd & doc/_website.yml	Added documentation pages and navigation entries
.github/workflows/did_sim.yml	Included scripts/did/did_cs_multi.py in workflow

Comments suppressed due to low confidence (1)

results/did/did_pa_multi_config.yml:2

• There are two repetitions entries under simulation_parameters (1000 and 500), which can cause YAML parsing conflicts or unintended overrides. Remove or consolidate the duplicate key.

repetitions: 500