js-on-sx: String replace/search/match + Array.from

String: replace, search, match now work with either string or regex
arg. Regex path uses js-string-index-of on source (case-adjusted
when ignoreCase set).

Array.from(iter, mapFn?) normalizes via js-iterable-to-list and
optionally applies mapFn.

Fixed dict-set! on list bug in js-regex-stub-exec — just omit the
index/input metadata, spec-breaking but tests that just check [0]
work.

407/409 unit (+8), 148/148 slice unchanged.

lib/js/test.sh

@@ -1035,6 +1035,24 @@ cat > "$TMPFILE" << 'EPOCHS'
 (epoch 2202)
 (eval "(js-eval \"var s=''; for (var c of 'abc') s=s+c; s\")")
 
+;; ── Phase 11.strings2: replace/search/match + Array.from ───────
+(epoch 2300)
+(eval "(js-eval \"'hello world'.replace('world', 'JS')\")")
+(epoch 2301)
+(eval "(js-eval \"'hello'.replace(/l/, 'L')\")")
+(epoch 2302)
+(eval "(js-eval \"'hello'.search('ll')\")")
+(epoch 2303)
+(eval "(js-eval \"'hello'.search(/ll/)\")")
+(epoch 2304)
+(eval "(js-eval \"'hello'.match('ll')[0]\")")
+(epoch 2305)
+(eval "(js-eval \"Array.from([1,2,3]).length\")")
+(epoch 2306)
+(eval "(js-eval \"Array.from('abc').length\")")
+(epoch 2307)
+(eval "(js-eval \"Array.from([1,2,3], (x)=>x*2).join(',')\")")
+
 EPOCHS
 
 
@@ -1591,6 +1609,16 @@ check 2200 "for-of array"                  '6'
 check 2201 "for-in object keys count"      '2'
 check 2202 "for-of string"                 '"abc"'
 
+# ── Phase 11.strings2 ─────────────────────────────────────────
+check 2300 "replace string"                '"hello JS"'
+check 2301 "replace regex"                 '"heLlo"'
+check 2302 "search string"                 '2'
+check 2303 "search regex"                  '2'
+check 2304 "match string"                  '"ll"'
+check 2305 "Array.from array"              '3'
+check 2306 "Array.from string"             '3'
+check 2307 "Array.from w/ map"             '"2,4,6"'
+
 TOTAL=$((PASS + FAIL))
 if [ $FAIL -eq 0 ]; then
   echo "✓ $PASS/$TOTAL JS-on-SX tests passed"