Support named weekdays (MON, TUE...) and months (JAN, FEB...) in cron expressions

[teesofttech]

Description

Many cron tools allow named weekdays (MON, TUE, WED, THU, FRI, SAT, SUN) and named months (JAN, FEB, MAR, etc.) in place of numbers. CronCraft does not currently normalize these before parsing, so expressions using text names produce incorrect results.

Current Behavior

"0 9 * JAN MON".ToHumanReadable(settings);
// → Incorrect/unexpected output

Expected Behavior

Named values should be normalized to their numeric equivalents before parsing:

"0 9 * JAN MON".ToHumanReadable(settings);
// → "Every Monday at 09:00 AM" (in January)

"0 9 * * MON-FRI".ToHumanReadable(settings);
// → "Every Monday through Friday at 09:00 AM"

"0 0 1 JAN,JUL *".ToHumanReadable(settings);
// → "Every year on January 1st and July 1st at 12:00 AM"

Normalization Map

Weekdays: SUN=0, MON=1, TUE=2, WED=3, THU=4, FRI=5, SAT=6

Months: JAN=1, FEB=2, MAR=3, APR=4, MAY=5, JUN=6, JUL=7, AUG=8, SEP=9, OCT=10, NOV=11, DEC=12

Where to Look

• CronCraft/Extensions/CronHelper.cs — add a normalization step in ConvertQuartzToCronos or at the start of BuildHumanReadable.

Acceptance Criteria

• All 7 weekday abbreviations are normalized before parsing
• All 12 month abbreviations are normalized before parsing
• Case-insensitive matching (e.g., mon, Mon, MON all work)
• Named values work in range and list patterns
• Unit tests cover all abbreviations and case variations