added new c.ReduceFuncs: FirstN, LastN, DictFirstN, DictLastN; optimi…

…zed in_ and not_in operators when len of sequence is 1

added Table.from_jsonl and Table.into_jsonl; added fill_value to Tabl…

…e.explode; fixed inlining to c.if_multiple

Add spread, zip_longest, statistical reducers (Variance/StdDev/Covari…

…ance/Correlation); fix Decimal support in Percentile/Median, asc/desc mutation, full join edge case

updated tests, Github Actions and pyproject.toml for Python 3.14

fixed `Table.pivot` for cases with prior table mutations

fixed some c.ReduceFuncs so they skip `None` values

fixed memory leaks in c.item & c.attr

fixed c.group_by CSE optimization

improved CSE (common subexpression elimination) dict c.ReduceFuncs

improved CSE (common subexpression elimination) for `c.group_by` mode