clean_units             Normalize/standardize units (placeholder)
conama_check            CONAMA conformity check (detailed; default
                        class = "2")
conama_limits           Limits for Brazilian CONAMA 357/2005
conama_report           CONAMA conformity report (table)
conama_summary          CONAMA conformity summary (long format)
conama_text             Text summary of conformity (bulleted,
                        formatted)
generate_analysis       Generate analytical paragraphs (rule-based)
iet_carlson             Trophic State Index (Carlson)
iet_lamparelli          Trophic State Index (Lamparelli)
iqa                     Water Quality Index (WQI / IQA)
nsfwqi                  NSF Water Quality Index (NSF WQI, prototype)
plot_box                Boxplots by site/parameter
plot_heatmap            Heatmap of parameters vs. sites
plot_iqa                Plot IQA by site/date
plot_map                Mapa interativo de pontos de coleta
plot_series             Time series by parameter
plot_trend              Linha de tendencia temporal para parametros de
                        qualidade da agua
read_wq                 Read water-quality CSV (robust parsing)
render_report           Render a water-quality report from the internal
                        R Markdown template
resume_wq               Descriptive summaries by group
trend_param             Tendencia monotona por parametro e ponto
                        (Theil-Sen + Spearman)
validate_wq             Validate presence of required columns
wq_demo                 Demo water quality dataset
