[W9] Documentation and geospatial community readiness

[Claudio9701]

Outcome

UrbanPy 0.3 installation, workflows, provider obligations, support, and contribution paths are accurate and reproducible.

Parent tasks

• modernize Sphinx and build with warnings as errors
• publish installation, task guides, API reference, schemas, and migration guide
• convert maintained notebooks and archive stale outputs
• add citation, governance, support, security, attribution, and data-license docs
• pursue conda-forge after stable PyPI release

Acceptance

A new user can install built artifacts and complete documented workflows without hidden maintainer knowledge.

Plan: PR #61