core: spec 35-var batch A — 1.11 parsers, map/partition variants, with-redefs, ns fns

Fifteen vars from the spec coverage gap (docs/spec/coverage.md):
parse-long/parse-double/parse-boolean (strict validation; scan-number alone
accepts 0x10), newline, current-time-ms (host clock for time), update-keys/
update-vals (PHM base, collisions last-wins), partitionv/partitionv-all/
splitv-at (lazy seqs of vectors; splitv-at's tail stays a seq, matching the
reference), with-redefs/with-redefs-fn (roots restored on throw), time,
macroexpand (expand-1 to fixpoint), alias/ns-unalias (write BOTH alias stores
— require :as uses string-keyed :imports while ns-aliases reads :aliases;
split filed), ns-publics (symbol-keyed map; publics == interns, no privacy).

Three pre-existing bugs fixed along the way:
- (partition n step pad coll) misparsed pad as the coll and returned ()
- (require 'bare.symbol) rejected — only vector specs were accepted
- analyze-form leaked the interpreted analyzer's ns on a punt: a throw out of
  the analyzer left current-ns=jolt.analyzer and :compile-ns set, so the
  fallback interpretation resolved user vars against the wrong namespace
  (bit (var user-sym) under compile mode)

And one overlay-authoring landmine documented in-code: a 20-coll fn must not
use 30-macros macros (with-redefs-fn's dotimes compiled as a forward ref that
resolved to the macro fn at runtime) — loop/recur instead.

Gate: conformance 316x3 (+14 rows), suite 4324 pass / 78 clean (was 4081/72;
parse_*/update_* files now contribute), baselines raised, all specs+unit,
fixpoint, self-host, sci, staged. Coverage: missing-portable 35 -> 20.

test/spec/namespaces-spec.janet

@@ -35,3 +35,10 @@
   ["require clojure.walk" "{:a 2}" "(do (require '[clojure.walk :as w]) (w/postwalk (fn [x] (if (number? x) (inc x) x)) {:a 1}))"]
   ["walk keywordize-keys" "{:a 1}" "(do (require '[clojure.walk :as w]) (w/keywordize-keys {\"a\" 1}))"]
   ["walk stringify-keys" "true"    "(do (require '[clojure.walk :as w]) (= {\"a\" 1} (w/stringify-keys {:a 1})))"])
+
+(defspec "namespaces / alias, ns-unalias, ns-publics"
+  ["alias + use"        "\"1,2\"" "(do (require (quote clojure.string)) (alias (quote st) (quote clojure.string)) (st/join \",\" [1 2]))"]
+  ["ns-unalias removes" "true"
+   "(do (require (quote clojure.string)) (alias (quote st2) (quote clojure.string)) (ns-unalias (quote user) (quote st2)) (nil? (get (ns-aliases (quote user)) (quote st2))))"]
+  ["ns-publics has var" "true"  "(do (def npv 1) (some? (get (ns-publics (quote user)) (quote npv))))"]
+  ["newline returns nil" "nil"  "(newline)"])