aoristic 2.0.0

• Added testthat edition 3 regression coverage for the 168-hour allocation, boundary conditions, invalid inputs, timezones, and daylight-saving changes.
• Replaced datetime reparsing and the one-second workaround with direct POSIXct arithmetic while preserving the published minute-level methodology.
• Preserved compatibility behavior for missing ends, reversed intervals, and intervals lasting at least one week.
• Added explicit input validation and corrected duplicate and uninitialized diagnostic-message handling.
• Updated package metadata, documentation, maintainer contact details, and CI.