The analyzer lowers the `.` special form (. target member arg*) and the
.-field field-access head to a :host-call instead of leaving them
uncompilable. Janet behaviour is unchanged — its back end punts :host-call
to the interpreter, which re-runs the original `.` form via eval-dot.
The Chez back end routes a non-shimmed :host-call through
record-method-dispatch, extended by a new host/chez/dot-forms.ss with the
arms dispatch-member covers but the record/string base did not, mirroring
src/jolt/interop/collections.janet precedence:
- collection interop first (count/seq/nth/get/valAt/containsKey on a
vector/map/set), so (. {:count 9} count) is the entry count like the seed
- field access for a "-name" member (records and maps)
- the seed's universal object-methods (getMessage/getCause/toString/
hashCode/equals) on a non-record map, winning over a field lookup
- non-record map member: a stored fn is a method called with self, else
the field value
Raw seqs are excluded from coll interop — the seed's behaviour there is
representation-dependent (plain (seq v) vs a lazy-seq) and a normalized cseq
can't mirror it. Also added getMessage/getLocalizedMessage/equals to the
string method surface so a thrown string / Exception. ctor (which keeps the
message string) answers .getMessage.
Parity 2134 -> 2150, 0 new divergences. New test/chez/_dotform.janet 26/26;
emit-test 331/331.
