Add --dates mode to extract operational date ranges

[xinwei89]

Summary

Adds a --dates mode to csv_tidy.py that parses the "Dates of use" column and emits a tidy CSV with Site ID, Start Date, End Date — one row per operational period.

Usage

python csv_tidy.py --dates --input data/carceral_tidy.csv --output data/carceral_dates.csv

Parsing rules

• Multiple periods: comma-separated periods each become their own row (e.g. 1826-1984, 2001-2002 -> two rows).
• Single year: start and end are the same (1847 -> 1847/1847).
• present/today: end becomes the current year.
• Decades: a decade is its first year at the start of a period but its last year at the end (1849-1870s -> 1849/1879; lone 1970s -> 1970/1979).
• Month/day detail preserved: October 1838 - November 1838 is kept verbatim.
• circa: leading c. / circa is ignored.
• Dash variants: hyphen, en dash, em dash all supported.
• Empty/junk cells -> ("", "").

Notes

• New parse_dates() and _format_endpoint() helpers.
• Mode dispatch priority: --shape > --dates > trim.

[wiz-8f2719713e]

Wiz Scan Summary

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IaC Misconfigurations	-
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