Fix: metadata review - DESCRIPTION title case and citation files

[larnsce]

Summary

Addresses #5

Changes Made

• Changed DESCRIPTION Title to title case: Data on Faecal Sludge Transporting Logistics in Kampala, Uganda (63 characters)
• Reworded Description opening from "This package contains" to "Contains" and fixed a double space
• Ran washr::update_description() (Date refreshed to 2026-07-08); restored Config/Needs/website packages (leaflet, htmlwidgets, webshot2) that washr stripped, as they are needed for the leaflet map article on CI
• Created inst/CITATION and regenerated CITATION.cff via washr::update_citation(doi = NULL); no DOI until the first release
• Removed the broken empty DOI badge that update_citation() injected into README.Rmd and rebuilt README.md
• Added CLAUDE.md to .Rbuildignore to avoid an R CMD check note
• Added CLAUDE.md (openwashdata standards file, written by /review-package)
• Rebuilt pkgdown site artifacts in docs/ as a side effect of update_citation()

Commits in this PR

• fix: use title case in DESCRIPTION title and tidy description text
• feat: add inst/CITATION and sync citation metadata via washr::update_citation()

Checklist

• Package name follows openwashdata conventions: clear, concise, and indicative of the data content
• Title is descriptive and under 65 characters
• Description is an informative and accurate statement of purpose
• Authors and maintainer clearly identified, with ORCID IDs and a contact email for the maintainer
• License: CC BY 4.0
• Dependencies properly declared
• Version follows semantic versioning
• If updates are made to DESCRIPTION, run washr::update_description()
• CITATION.cff file present and valid
• Version in CITATION.cff matches the version in DESCRIPTION
• Generate citation using washr::update_citation() (without a DOI until the first release)

R CMD check: 0 errors, 0 warnings, 0 notes.

Closes #5