feat: Custom dayjs.parse()

[distantnative]

Description

I think this one is hard to read the code to review. Probably better to just test it out via the lab example. Trying to explain the changed approach:

dayjs.interpret() used to guess what a user typed by throwing the input at a hardcoded list of ~70 format strings and taking the first that stuck. Often rather faulty as the number of long-around bug reports shows.

This PR introduces dayjs.parse() that replaces the dayjs core plugin customParseFormat and our previous dayjs.interpret(). It follows the following path:

1. Match the pattern first: We have the display format pattern usually. And it's not unlikely the user will type something in that follows that pattern somewhat. So the input is split into tokens and matched positionally against the display pattern's parts. Neither the separators nor the number widths have to match exactly (e.g. a DD.MM.YYYY pattern still reads 2/3/24, 02.03.2024 and even 02032024), but it has to offer something sensible for all parts of the display pattern to be used.
2. If that fails, then guess, but still informed by the pattern. Anything the pattern can't read exactly (partial input, another unit order) falls back to a small list of unit orders. dayjs.interpret() threw a long list at it, often faulty. But even when guessing, the display pattern should inform our guesses about which order to prioritize etc. So we test a list of guesses, but only guesses that use units the pattern also shows. And the ones agreeing with the pattern's order go first. strict: true skips this step entirely.

Because both iso() and parse() now build datetimes explicitly, the customParseFormat dayjs plugin is no longer needed.

DateInput still calls the deprecated interpret() without a pattern. Wiring the inputs up to parse() and their display pattern is happening in: #8322

Merge first

• fix: Strict dayjs.iso() parsing #8325

Changelog

✨ Enhancements

• New $library.dayjs.parse(input, { pattern, strict, type }): parses what a user types against a display pattern to create a date time object.
• Date field: Localized month names are recognized in English, including abbreviations. (and with feat: Locale support for dayjs #8327 also in the current Panel UI locale)

☠️ Deprecated

• $library.dayjs.interpret() is deprecated. Use $library.dayjs.parse() instead.

For review team

• Add lab and/or sandbox examples (wherever helpful)
  • https://sandbox.test/panel/lab/internals/library.dayjs/2_pattern
  • https://sandbox.test/panel/lab/internals/library.dayjs/3_parse
• Add changes & docs to release notes draft in Notion

[bastianallgeier]

I only quickly started to test the lab and wanted to change the format. But when I try, I immediately run into an error:

TypeError: can't access property "matchAll", this.source is undefined

Am I not supposed to change the format or is this an issue?

[distantnative]

@bastianallgeier sorry seems at the end when cleaning up I renamed one string in the lab example wrongly.

[bastianallgeier]

I've tested the pattern and parse tabs in the lab and it works really great.