A ^RecordType hint only resolved against the current namespace's ctor key, so a
hint naming a record defined in another namespace degraded to :any. That made a
decomposed multi-namespace program much slower than the monolith: per-namespace
inference can't see a record param's callers in other namespaces, and the
declared hint that could have typed it was dropped.
Resolution now works cross-namespace, for both record FIELD hints (defrecord)
and fn PARAM hints, in both spellings — ^Vec3 where the type is referred and
^v/Vec3 where the namespace is aliased:
- reader keeps a tag's namespace qualifier (^t/Ray -> "t/Ray", was "Ray").
- make-deftype-ctor-impl indexes each ctor closure by value; record-hint-ctor-key
resolves a hint name against the COMPILE ns (referred names live there; aliases
resolve through it) and maps the type var's root back to its home ctor key.
Using the ctor value, not the var's :ns, is what makes :refer work — :refer
re-interns a fresh var whose :ns is the referring ns.
- the analyzer captures record param hints as arity :phints [name ctor-key];
reinfer-def seeds those param types, so a record param is typed even with no
inferred caller — the open-world / cross-ns case.
Effect on the multi-namespace ray tracer: per-ns compile 30.4s -> 7.9s with
param hints, matching whole-program (8.1s) and the single-ns monolith (8.3s).
cross-ns-hints-test covers field + param hints, refer + as, and the reader tag.
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