feat(strictness): num/cons/realized?/symbol/keyword reject malformed args

- num throws on non-numbers (no longer coerces chars)
- cons throws when the second arg isn't seqable (a number/keyword/boolean/fn)
- realized? throws on non-IPending values (only delays/promises/lazy-seqs)
- symbol: 1-arg accepts string/symbol/keyword (->symbol), throws otherwise;
  2-arg requires string ns (nil ok) and string name
- keyword: (keyword nil) is nil, 1-arg accepts string/symbol/keyword, 2-arg
  requires string name and nil-or-string ns

keyword file clean; symbol 60/0/1; cons 18/1/1; realized? 25/1/0.
clojure-test-suite pass 3738->3781. spec: seq/strictness (13). jpm test green.

test/integration/clojure-test-suite-test.janet

@@ -18,7 +18,7 @@
 
 # Baseline: assertions Jolt currently passes across the suite. Raise as Jolt
 # improves so a regression (previously-passing assertion breaking) is caught.
-(def baseline-pass 3730)
+(def baseline-pass 3770)
 # A file is "clean" when it ran with zero failures AND zero errors.
 (def baseline-clean-files 45)
 # Per-file wall-clock budget (seconds). Normal files finish in well under 1s;