runtime/object-model: function this binding, primitive boxing, and call/apply behavior #3586

Summary

Track function-code failures around strict/sloppy this, primitive receiver boxing, callback receiver binding, and callable Function.prototype paths.

Child issues

• runtime/object-model: implement strict and sloppy function this binding #3576
• runtime/object-model: support primitive receiver boxing and temporary property visibility #3577
• runtime/object-model: pass correct this binding to callback invocations such as String.replace #3578
• runtime/object-model: make Function.prototype call/apply paths callable in function-code tests #3579

Scope notes

• Treat these as Perry ECMAScript/runtime-language semantics gaps, not Node stdlib parity.
• Likely subsystems are parser, HIR lowering, codegen, runtime object model, async scheduling, or error/throw semantics.
• Eval/runtime-dynamic-code rows are excluded separately under Perry's AOT policy.

Validation

scripts/test262_subset.py --root vendor/test262 --dir language/function-code --sample-cap 99999 --report /tmp/perry-test262-function-code.json

Acceptance for this epic: every linked child issue has a focused regression or Test262 validation path, and the affected rows are removed from the gap report without introducing duplicate issue coverage.