docs: Restructure documentation to reflect package decomposition into subpackages and methods

[Copilot]

The package has been decomposed into common modules (power_spectra, data_vector, data) and distinct method subpackages (covariance, simulation, field comparison), but the docs still reflected the old monolithic structure.

New pages

• overview.rst — Package structure overview: common modules vs. method subpackages
• covariance_method.rst — Likelihood-based field-level inference method (arXiv:2501.16852), analytical models, usage workflow
• simulation.rst — Forward modeling simulation (under construction)
• field_comparison.rst — Field comparison method (not yet implemented)

Updated pages

• index.rst — Three toctree sections: "Getting started", "Common modules", "Methods"
• conf.py — autoapi_dirs extended to cover all subpackages (data_vector, power_spectra, data, simulation)
• power_spectra.rst — Broken markdown fences → proper RST code-block directives; added engine/model docs
• likelihoods.rst — Fixed malformed LaTeX (backtick-wrapped math blocks); added inversion methods section; linked to covariance method
• DataVector.rst — Contextualized as a shared module

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• docs.astropy.org
  • Triggering command: /usr/bin/python python -m sphinx -b html . _build/html (dns block)
• docs.python.org
  • Triggering command: /usr/bin/python python -m sphinx -b html . _build/html (dns block)
• docs.scipy.org
  • Triggering command: /usr/bin/python python -m sphinx -b html . _build/html (dns block)
• pandas.pydata.org
  • Triggering command: /usr/bin/python python -m sphinx -b html . _build/html (dns block)
• sncosmo.readthedocs.io
  • Triggering command: /usr/bin/python python -m sphinx -b html . _build/html (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

---

💬 Send tasks to Copilot coding agent from Slack and Teams to turn conversations into code. Copilot posts an update in your thread when it's finished.