[proggeramlug]

Closes #2770
Closes #2771
Closes #2772

Implementation

Map/Set/WeakMap/WeakSet constructors now implement spec-faithful
AddEntriesFromIterable / Set-constructor iterable consumption, and the weak
mutators validate at runtime.

New shared module crates/perry-runtime/src/collection_iter.rs:

• classify_init(value) — null/undefined → empty; any iterable (Array,
  String, Map, Set, custom [Symbol.iterator]) → materialized value array via
  the existing js_for_of_to_array; everything else → throws Node's exact
  TypeError: <type> [<value> ]is not iterable (cannot read property Symbol(Symbol.iterator)) (number/boolean print the value; bigint/symbol/
  function/object print just the type word).
• is_entry_object / throw_not_entry_object — Map/WeakMap require each
  yielded value to be an object, else TypeError: Iterator value <v> is not an entry object.

Per-collection wiring:

• Map (runtime: make Map constructor consume iterable entries and throw on malformed init #2770): new js_map_from_iterable(f64) reads entry [0]/[1] via
  the polymorphic index getter (so [['k']] and [[]] keep undefined
  components); codegen passes the NaN-boxed init value (DOUBLE) instead of an
  unboxed ArrayHeader. #[used] keepalive anchor added (codegen-only symbol).
• Set (runtime: make Set constructor consume arbitrary iterables and throw on non-iterables #2771): js_set_from_iterable rewritten to consume the materialized
  array and throw on non-iterables (no codegen change; it already took f64).
• WeakMap/WeakSet (runtime: make WeakMap and WeakSet constructors and mutators reject invalid init values #2772): js_weakmap_init_iterable /
  js_weakset_init_iterable consume arbitrary iterables + validate entries;
  js_weakmap_set / js_weakset_add validate keys/values at runtime and throw
  Invalid value used as weak map key / Invalid value used in weak set. The
  AST-literal-only primitive throw in HIR lowering was removed so literal and
  dynamic primitives are rejected uniformly with the correct distinct messages.

Validation

• New gap test test-files/test_gap_collections_2770_2771_2772.ts is
  byte-identical to node --experimental-strip-types under the DEFAULT
  auto-optimize compile (covers iterable consumption, short/empty entries,
  null/undefined init, and every TypeError message above).
• js_map_from_iterable symbol confirmed present in the auto-optimize
  libperry_runtime.a (keepalive survives the whole-program bitcode link).
• ./scripts/check_file_size.sh → OK; cargo fmt --all -- --check → clean.
• cargo test -p perry-runtime (896 collection/runtime tests pass; one
  unrelated GC-barrier ordering flake passes in isolation) and
  cargo test -p perry-hir (incl. expr_variant_stable_hash_tags_are_unique)
  green.
• Regression-checked 7 existing Map/Set/Weak test files
  (test_gap_map_from_map, test_edge_map_set, test_gap_map_set_extended,
  test_gap_weakmap_dynamic, test_gap_for_of_untyped_map_set,
  test_gap_json_map_set, test_gap_map_set_entries_dispatch) — all stay
  byte-identical to node.

Note

new WeakMap(null) instanceof WeakMap returning false is a pre-existing,
orthogonal Perry gap (instanceof WeakMap is false even for new WeakMap());
it is not regressed here. The constructor correctly produces a functional weak
collection for null/undefined init, so the gap test asserts that behavior
functionally (set/get/has) rather than via the unrelated instanceof.