test+docs: spec coverage for migratus-enablement fixes; list migratus
Adds spec/conformance coverage for everything landed enabling migratus:
- conformance corpus (runs interpret/compile/self-host): def 3-arg docstring,
def/defn ^{:map} name meta, defmacro arity-clause + docstring, defmulti
docstring, assoc-nil/assoc-in real maps, try multi-body + finally-on-success,
current-ns restore after a caught throw, cross-ns methods visibility.
- spec suites: host-interop (exception ctors, Character/Thread/Long, Timestamp/
SimpleDateFormat, java.io.File model + File-aware file-seq, clojure.tools.logging),
regex (Pattern statics + MULTILINE + quote, String .matches/.replaceAll/
.replaceFirst), maps (assoc on nil), multimethods (defmulti docstring +
value-based methods/get-method), macros (defmacro arity-clause + name meta).
Rewrote clojure.tools.logging/spy as a single variadic arity (jolt defmacro
takes only the first clause of a multi-arity macro — jolt-q8l).
docs/libraries.md: add migratus and the next.jdbc compatibility layer, with the
janet-lang/sqlite3 int64 caveat for 14-digit timestamp ids.
Full gate green; conformance 350/350 x3 modes.
72e36f46de