Store time.Time in a format compatible with sqlite's date/time funcs

[thehowl]

https://www.sqlite.org/lang_datefunc.html

SQLite does not have a dedicated date/time datatype. Instead, date and time values can stored as any of the following:
ISO-8601: A text string that is one of the ISO 8601 date/time values shown in items 1 through 10 below. Example: '2025-05-29 14:16:00'
Julian day number The number of days including fractional days since -4713-11-24 12:00:00 Example: 2460825.09444444
Unix timestamp The number of seconds including fractional seconds since 1970-01-01 00:00:00 Example: 1748528160