js-on-sx: Array.prototype includes/find/some/every/reverse + Object fallbacks

Array: includes, find, findIndex, some, every, reverse via
tail-recursive helpers.

Object: hasOwnProperty, isPrototypeOf, propertyIsEnumerable,
toString, valueOf, toLocaleString fallback in js-invoke-method
when js-get-prop returns undefined. Lets o.hasOwnProperty('k')
work on plain dicts.

376/378 unit (+13), 148/148 slice unchanged.

lib/js/test.sh

@@ -951,6 +951,36 @@ cat > "$TMPFILE" << 'EPOCHS'
 (epoch 1605)
 (eval "(js-eval \"var r=0; switch(1){case 1: r=10; case 2: r=20; break;} r\")")
 
+;; ── Phase 11.array: more Array.prototype ────────────────────────
+(epoch 1700)
+(eval "(js-eval \"[1,2,3].includes(2)\")")
+(epoch 1701)
+(eval "(js-eval \"[1,2,3].includes(5)\")")
+(epoch 1702)
+(eval "(js-eval \"[1,2,3].find((x)=>x>1)\")")
+(epoch 1703)
+(eval "(js-eval \"[1,2,3].findIndex((x)=>x>1)\")")
+(epoch 1704)
+(eval "(js-eval \"[1,2,3].some((x)=>x>2)\")")
+(epoch 1705)
+(eval "(js-eval \"[1,2,3].some((x)=>x>5)\")")
+(epoch 1706)
+(eval "(js-eval \"[1,2,3].every((x)=>x>0)\")")
+(epoch 1707)
+(eval "(js-eval \"[1,2,3].every((x)=>x>2)\")")
+(epoch 1708)
+(eval "(js-eval \"[1,2,3].reverse().join(',')\")")
+
+;; ── Phase 11.objmethod: hasOwnProperty + toString ───────────────
+(epoch 1800)
+(eval "(js-eval \"var o = {x:1}; o.hasOwnProperty('x')\")")
+(epoch 1801)
+(eval "(js-eval \"var o = {x:1}; o.hasOwnProperty('y')\")")
+(epoch 1802)
+(eval "(js-eval \"({}).toString()\")")
+(epoch 1803)
+(eval "(js-eval \"({x:1}).valueOf().x\")")
+
 EPOCHS
 
 OUTPUT=$(timeout 180 "$SX_SERVER" < "$TMPFILE" 2>/dev/null)
@@ -1458,6 +1488,23 @@ check 1603 "switch fallthrough stops on break" '12'
 check 1604 "switch on string"              '"yes"'
 check 1605 "switch fallthrough chains"     '20'
 
+# ── Phase 11.array: more Array.prototype ────────────────────────
+check 1700 "Array.includes yes"            'true'
+check 1701 "Array.includes no"             'false'
+check 1702 "Array.find"                    '2'
+check 1703 "Array.findIndex"               '1'
+check 1704 "Array.some yes"                'true'
+check 1705 "Array.some no"                 'false'
+check 1706 "Array.every yes"               'true'
+check 1707 "Array.every no"                'false'
+check 1708 "Array.reverse"                 '"3,2,1"'
+
+# ── Phase 11.objmethod: hasOwnProperty ──────────────────────────
+check 1800 "hasOwnProperty yes"            'true'
+check 1801 "hasOwnProperty no"             'false'
+check 1802 "({}).toString()"               '"[object Object]"'
+check 1803 "obj.valueOf().x"               '1'
+
 TOTAL=$((PASS + FAIL))
 if [ $FAIL -eq 0 ]; then
   echo "✓ $PASS/$TOTAL JS-on-SX tests passed"