Allow script arrays to hold any value type, add script engine tests, archive old rpg code

Remove the per-array type category so arrays can mix types like structs.
Add 13 passing and 125 expected-failure duskscript test fixtures with a
table-driven runner. Also includes the in-progress entity/physics and
archive moves from the working tree.

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>

test/duskscript/assets/pass_constants.ds

@@ -0,0 +1,70 @@
+const LIMIT = 10;
+const NAME = "dusk";
+const FLAG = true;
+const NOTHING = null;
+const RATIO = 2.5;
+assert(LIMIT == 10);
+assert(NAME == "dusk");
+assert(FLAG);
+assert(isnull(NOTHING));
+assert(RATIO * 2 == 5);
+assert(LIMIT + 1 == 11);
+assert(NAME + "!" == "dusk!");
+assert(len(NAME) == 4);
+var total = 0;
+for(var i = 0; i < LIMIT; i++) total += 1;
+assert(total == LIMIT);
+
+// Constant arrays and structs can be read
+const LIST = [1, "two", [3, 4], {five: 5}];
+assert(len(LIST) == 4);
+assert(LIST[0] == 1);
+assert(LIST[1] == "two");
+assert(LIST[2][1] == 4);
+assert(LIST[3].five == 5);
+const CONFIG = {name: "cfg", nested: {depth: 2, items: [10, 20]}, on: true};
+assert(CONFIG.name == "cfg");
+assert(CONFIG.nested.depth == 2);
+assert(CONFIG.nested.items[1] == 20);
+assert(CONFIG["nested"]["items"][0] == 10);
+assert(CONFIG.on);
+assert(isundefined(CONFIG.missing));
+foreach(var item : LIST) assert(!isundefined(item));
+assert(join(map(CONFIG.nested.items, function(v) { return v; }), ",") == "10,20");
+assert(indexof(LIST, 1) == 0);
+
+// Constant functions
+function helper(n) {
+  return n + LIMIT;
+}
+assert(helper(1) == 11);
+
+// Copies of constants can be changed, the constant itself stays as it was
+var copy = clone(LIST);
+push(copy, "extra");
+copy[0] = "changed";
+assert(len(copy) == 5 && copy[0] == "changed");
+assert(len(LIST) == 4 && LIST[0] == 1);
+var deep = deepclone(CONFIG);
+deep.name = "other";
+deep.nested.items[0] = 99;
+assert(CONFIG.name == "cfg");
+assert(CONFIG.nested.items[0] == 10);
+assert(deep.nested.items[0] == 99);
+var fromConst = LIMIT;
+fromConst++;
+assert(fromConst == 11);
+assert(LIMIT == 10);
+
+// A constant in a function that is called more than once
+function useName() {
+  return NAME + "?";
+}
+assert(useName() == "dusk?");
+assert(useName() == "dusk?");
+
+// A constant built from other constants
+const DOUBLE = LIMIT * 2;
+assert(DOUBLE == 20);
+const GREETING = NAME + " " + "engine";
+assert(GREETING == "dusk engine");