introduce a date length setting

* java.time and java.util.Date deserialization
* the string values that we need to parse - they shouldn't be very long - AI suggests 50 is valid limit
* the processing time on something bound by our string limit (default 20,000) may not be terrible - the parse complexity is apparently not exponential like number parsing
* if we do limit, we could hardcode a value or we could make it configurable
* or we could reuse the number len constraint but it feels like a bit much to reuse that for dates in formats like ISO-8601 or similar date/time specific formats

Start by locating the java.time and java.util.Date deserialization entry points and reviewing the existing string or number length constraints. The issue needs a decision on whether the date length limit is hardcoded or configurable, followed by tests that cover the chosen limit and confirm deserialization behavior.

Written by the indexing model from the issue text.