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/macros-spec.janet

@@ -72,3 +72,16 @@
   ["binding rebinds"     "99"     "(do (def ^:dynamic *bx* 10) (binding [*bx* 99] *bx*))"]
   ["binding restores"    "10"     "(do (def ^:dynamic *by* 10) (binding [*by* 99] *by*) *by*)"]
   ["binding seen by fn"  "7"      "(do (def ^:dynamic *bz* 0) (defn rdz [] *bz*) (binding [*bz* 7] (rdz)))"])
+
+# time returns the body value (the timing line goes to *out*); with-redefs
+# temporarily rebinds var roots and restores on exit (even on throw);
+# macroexpand expands repeatedly until the head is no longer a macro.
+(defspec "macros / time, with-redefs, macroexpand"
+  ["time returns value"  "3"      "(time (+ 1 2))"]
+  ["with-redefs rebinds" "42"     "(do (defn wr-f [] 1) (with-redefs [wr-f (fn [] 42)] (wr-f)))"]
+  ["with-redefs restores" "1"     "(do (defn wr-g [] 1) (with-redefs [wr-g (fn [] 42)]) (wr-g))"]
+  ["with-redefs restores on throw" "1"
+   "(do (defn wr-h [] 1) (try (with-redefs [wr-h (fn [] 42)] (throw (ex-info \"x\" {}))) (catch :default e nil)) (wr-h))"]
+  ["with-redefs-fn"      "42"     "(do (defn wr-i [] 1) (with-redefs-fn {(var wr-i) (fn [] 42)} (fn [] (wr-i))))"]
+  ["macroexpand full"    "true"   "(let [e (macroexpand (quote (when-not false 1)))] (= (quote if) (first e)))"]
+  ["macroexpand non-macro" "[1 2]" "(macroexpand (quote [1 2]))"])