fix(hir): language/expressions/object literal semantics test262 parity

[proggeramlug]

Root cause

Object-literal method definitions ({ m([x, y]) {} }, { m(a = 23) {} }) lowered their parameters in crates/perry-hir/src/lower/expr_object.rs (lower_method_prop) without:

1. destructuring-extraction statements — a method param like [x, y, z] never produced a Let for x/y/z, so the body threw ReferenceError: identifier is not defined;
2. default-parameter fill statements — object methods never dispatch through the __perry_wrap_<name> prologue that applies a top-level function's registered defaults, so without the body carrying its own if (p === undefined) p = <default> checks, every defaulted param read as undefined.

Plain functions (lower_fn_decl/expr_function) and class methods (lower_decl/class_members.rs) already do both; the object-literal method path was the one site missing it.

Fix

Mirror lower_decl/class_members.rs exactly:

• Unwrap Pat::Assign to the inner array/object pattern before the is_destructuring_pattern check — [x] = [1] is a Pat::Assign wrapping the pattern, so checking the raw param.pat missed the defaulted-destructuring form.
• generate_param_destructuring_stmts before lowering the body, so the destructured bindings are in scope when the body references them.
• Prepend build_default_param_stmts last, so defaults run before destructuring (m([x] = [1]) {}).

Files touched: crates/perry-hir/src/lower/expr_object.rs (only).

Results — language/expressions/object

453 → 557 pass (+104), zero regressions.

Measured with two isolated runs of both baseline (origin/main @ 25ccfbb) and fix; both pairs were byte-identical (0 flaky), 0 tests that passed before now fail. Default compile path (no env flags).

Fixed families (all the same root cause):

• dstr/ meth / gen-meth / async-gen-meth (+ -dflt variants) destructuring params — ~90 tests
• method-definition/ meth-dflt-params / gen-meth-dflt-params / async-meth-dflt-params default-param edge cases
• scope-{,gen-}meth-param-* var-scope cases

Remaining failures in the directory are unrelated (lone eval(...) of string code, fn.name descriptor edge cases, super-in-object-method, async-generator yield* delegation).