core.contracts: fully passes, two general fixes

clojure.core.contracts (over core.unify) now runs its whole suite on jolt —
14/14 across contracts/constraints/with-constraints/provide tests. Two general
gaps fixed:

- Symbol and Keyword now report IFn (and Fn/Runnable/Callable) in the modeled
  class hierarchy, so a (class x)-dispatched multimethod with an IFn method
  matches a symbol or keyword, like the JVM (both implement IFn — they're
  callable). core.contracts' funcify* dispatches on (class constraint) and a
  bare predicate symbol must hit the IFn arm. Runtime, no re-mint.
- A live Var value spliced into a form by a macro (defcurry-from resolves a var
  and emits (~v l r)) now compiles: analyze treats a var-cell form as a
  :the-var reference by ns+name, the same node as (var ns/name), mirroring the
  existing spliced-namespace (~*ns*) case. analyzer.clj + host-contract.ss,
  re-mint (prelude stays byte-identical; only the analyzer image changes).

Listed in docs/libraries.md + the site.

make test green (+2 corpus rows, 0 new divergences), shakesmoke byte-identical.

docs/libraries.md

@@ -54,6 +54,9 @@ e.g. the [ring-app example](https://github.com/jolt-lang/examples/tree/main/ring
   (unification, `run`/`fresh`/`conde`, finite domains).
 * [math.combinatorics](https://github.com/clojure/math.combinatorics) — permutations,
   combinations, subsets, selections, cartesian products, partitions.
+* [core.contracts](https://github.com/clojure/core.contracts) — programming by
+  contract (`contract`/`with-constraints`/`provide`), over
+  [core.unify](https://github.com/clojure/core.unify).
 * [tick](https://github.com/juxt/tick) — date/time over Jolt's `java.time`;
   `#time/…` literals via `time-literals`.
 * [transit-jolt](https://github.com/jolt-lang/transit-jolt) — Transit (JSON) read/write