test: fold cljs ports into spec; add exceptions spec + gap coverage

Mine the cljs port batteries into the spec layer and delete them (their behavior
is covered by spec; the unique functions they exercised are now specced).
Removed test/integration/ports/ entirely.

New/expanded spec coverage from the mining:
- spec/exceptions-spec: try/catch/finally, throw, ex-info/ex-message/ex-data/ex-cause
- doto, pr-str, keyword/symbol constructors, atom?, dynamic var binding

Two rare edges filed (jolt-...): rethrow of a caught ex-info re-wraps it; var-set
on a dynamic var inside binding no-ops. Core try/catch/ex-info and binding work.

Test layout is now spec (22 files, ~677 cases) / integration / unit / support.
conformance 218/218, jpm test green.

test/spec/control-flow-spec.janet

@@ -59,4 +59,5 @@
   ["some-> nil stops"   "nil"    "(some-> nil inc)"]
   ["some->>"            "[2 3]"  "(some->> [1 2] (map inc))"]
   ["cond->"             "2"      "(cond-> 1 true inc false inc)"]
-  ["cond->>"            "[1 2]"  "(cond->> [2] true (cons 1))"])
+  ["cond->>"            "[1 2]"  "(cond->> [2] true (cons 1))"]
+  ["doto returns subject" "5"    "(let [a (doto (atom 0) (reset! 5))] @a)"])

test/spec/exceptions-spec.janet

@@ -0,0 +1,28 @@
+# Specification: exceptions — try/catch/finally, throw, ex-info.
+(use ../support/harness)
+
+(defspec "exceptions / try-catch"
+  ["catch :default"      ":caught"
+   "(try (throw (ex-info \"boom\" {})) (catch :default e :caught))"]
+  ["catch by class"      ":caught"
+   "(try (throw (ex-info \"boom\" {})) (catch Exception e :caught))"]
+  ["catch binds error"   "\"boom\""
+   "(try (throw (ex-info \"boom\" {})) (catch :default e (ex-message e)))"]
+  ["no throw -> body"    "1"
+   "(try 1 (catch :default e :caught))"]
+  ["finally runs on ok"  "2"
+   "(let [a (atom 0)] (try 2 (finally (reset! a 9))) )"]
+  ["finally runs on throw" "9"
+   "(let [a (atom 0)] (try (throw (ex-info \"x\" {})) (catch :default e nil) (finally (reset! a 9))) @a)"]
+  ["catch value of body" "5"
+   "(try (+ 2 3) (catch :default e 0))"])
+
+(defspec "exceptions / ex-info"
+  ["ex-message"          "\"oops\""  "(ex-message (ex-info \"oops\" {}))"]
+  ["ex-data"             "{:k 1}"    "(ex-data (ex-info \"oops\" {:k 1}))"]
+  ["ex-data via catch"   "{:code 42}"
+   "(try (throw (ex-info \"e\" {:code 42})) (catch :default e (ex-data e)))"]
+  ["ex-cause"            "true"
+   "(let [c (ex-info \"root\" {})] (= c (ex-cause (ex-info \"outer\" {} c))))"]
+  ["propagates to outer"  "\"inner\""
+   "(try (try (throw (ex-info \"inner\" {})) (finally nil)) (catch :default e (ex-message e)))"])

test/spec/namespaces-spec.janet

@@ -9,7 +9,9 @@
   ["var sugar #'"       "true"     "(var? #'+)"]
   ["var-get"            "5"        "(do (def w 5) (var-get #'w))"]
   ["defn defines fn"    "3"        "(do (defn f [x] (inc x)) (f 2))"]
-  ["def with docstring" "7"        "(do (def d \"a doc\" 7) d)"])
+  ["def with docstring" "7"        "(do (def d \"a doc\" 7) d)"]
+  ["dynamic var binding" "2"       "(do (def ^:dynamic *x* 1) (binding [*x* 2] *x*))"]
+  ["binding restores"    "1"       "(do (def ^:dynamic *y* 1) (binding [*y* 9] nil) *y*)"])
 
 (defspec "namespaces / ns operations"
   ["in-ns switches"     "true"     "(do (in-ns 'my.ns) (symbol? 'x))"]

test/spec/predicates-spec.janet

@@ -47,7 +47,11 @@
   ["name of keyword"    "\"a\""  "(name :a)"]
   ["name of qualified"  "\"b\""  "(name :a/b)"]
   ["namespace"          "\"a\""  "(namespace :a/b)"]
-  ["namespace simple"   "nil"    "(namespace :a)"])
+  ["namespace simple"   "nil"    "(namespace :a)"]
+  ["keyword constructor" ":foo"  "(keyword \"foo\")"]
+  ["keyword ns + name"  ":a/b"   "(keyword \"a\" \"b\")"]
+  ["symbol constructor" "(quote x)" "(symbol \"x\")"]
+  ["name of string"     "\"s\""  "(name \"s\")"])
 
 (defspec "predicates / equality & identity"
   ["= same"             "true"   "(= 1 1)"]

test/spec/state-spec.janet

@@ -13,7 +13,9 @@
   ["reset-vals!"        "[0 9]"  "(let [a (atom 0)] (reset-vals! a 9))"]
   ["compare-and-set! ok" "true"  "(let [a (atom 0)] (compare-and-set! a 0 1))"]
   ["compare-and-set! no" "false" "(let [a (atom 0)] (compare-and-set! a 9 1))"]
-  ["atom?"              "true"   "(do (require (quote [clojure.core])) (instance? clojure.lang.Atom (atom 0)))"])
+  ["atom?"              "true"   "(do (require (quote [clojure.core])) (instance? clojure.lang.Atom (atom 0)))"]
+  ["atom? predicate"    "true"   "(atom? (atom 0))"]
+  ["atom? on non-atom"  "false"  "(atom? 5)"])
 
 (defspec "state / watches & validators"
   ["add-watch fires"    "1"      "(let [a (atom 0) seen (atom 0)] (add-watch a :k (fn [k r o n] (reset! seen 1))) (reset! a 5) @seen)"]

test/spec/strings-spec.janet

@@ -11,6 +11,8 @@
   ["subs from"          "\"bc\""     "(subs \"abc\" 1)"]
   ["subs range"         "\"b\""      "(subs \"abc\" 1 2)"]
   ["string? true"       "true"       "(string? \"x\")"]
+  ["pr-str vector"      "\"[1 2 3]\"" "(pr-str [1 2 3])"]
+  ["pr-str quotes str"  "\"\\\"hi\\\"\"" "(pr-str \"hi\")"]
   ["seq of string"      "[\\a \\b]"  "(seq \"ab\")"])
 
 (defspec "clojure.string"