Timestap format should be human-readable

[JosuaCarl]

New feature

The current timestamp format is: "yyyyMMdd-A", producing something like 20250326-57453015. Especially the last part (A = milliseconds of a day) is very bad to read, although the first part is also pretty uneasy on the eye.

Use case

• Looking at Trace files and searching the last run
• Using the Trace timestamp for writing other timestamped output (for example in plugins) in a human-readable format.

Suggested implementation

I like the nf-core standard timestamp yyyy-MM-dd_HH-mm-ss. If more specificity is desired (milli- or even nanoseconds), one could change this to yyyy-MM-dd_HH-mm-ss-n.

Position of code:

nextflow/modules/nextflow/src/main/groovy/nextflow/trace/TraceHelper.groovy

Lines 51 to 55 in 4be204f

	@Memoized
	static private String fmt(Instant instance) {
	final formatter = DateTimeFormatter.ofPattern("yyyyMMdd-A").withZone(ZoneId.systemDefault())
	return formatter.format(instance)
	}

[bentsherman]

@pditommaso I think you were the one who proposed this format, perhaps you can explain