core: migrate repeatedly to Clojure + fix char-not-callable / take count validation

Resolves the deferred repeatedly port (jolt-8qx). The blockers were two jolt
leniencies vs Clojure, now fixed (and correct beyond repeatedly):

- A char (a :jolt/type-tagged struct) fell into the struct-as-map branch of both
  jolt-call (compile path) and the interpreter's apply dispatch, so (\a) returned
  nil instead of throwing. Now only an UNtagged struct (a map literal) — or a
  record — is callable as a key lookup; tagged structs fall through to "Cannot
  call … as a function". Symbols are still handled (keyword-style get).
- core-take didn't validate its count, letting Janet's >= silently compare an int
  to a char/string. It now rejects a non-number n like Clojure.

With those, the canonical CLJ repeatedly matches: (first (repeatedly non-fn)) and
(repeatedly non-number f) throw. Moved repeatedly to core/40-lazy.clj; removed
core-repeatedly + its binding from the seed.

These correctness fixes help broadly: repeatedly.cljc goes clean (19/10 -> 29/0),
and the suite rises 4004 -> 4034 pass / 66 -> 67 clean. Baseline raised.

Gate: conformance 262x3, lazy-infinite 44/44, clojure-test-suite 4034/67,
fixpoint, self-host, sci, fallback-zero, specs+unit green.

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

@@ -40,9 +40,9 @@
 # many cross-dialect files). Stable across runs.
 # Raised 3981 -> 4004 migrating 7 lazy seq fns to the Clojure overlay (40-lazy
 # tier): the canonical CLJ versions add coverage (e.g. distinct value-equality).
-(def baseline-pass 4004)
+(def baseline-pass 4034)
 # A file is "clean" when it ran with zero failures AND zero errors.
-(def baseline-clean-files 66)
+(def baseline-clean-files 67)
 # Per-file wall-clock budget (seconds). Normal files finish in well under 1s, so
 # this normally only fires on genuinely-infinite-sequence hangs. It's an env var
 # (JOLT_SUITE_TIMEOUT) so CI — whose runners are slower than a dev machine — can