INT-OBJECT-01O: Execute owned metaclass instance checks #270

Scope

Implement metaclass instancecheck and native type.instancecheck through owned operations and ordinary callback frames. Preserve exact-real-type shortcut, actual/advertised class defaults, descriptor binding, truth conversion, tuple order, source errors, bounded recursion/work/allocation, collection, cancellation and zero logical teardown. Enable only its adopted corpus stage.

Dependencies and acceptance

Parent: #123 (INT-OBJECT-01). Depends on INT-OBJECT-01N.

Use the existing JavaScript execution machine, explicit classes-source/1 and bytecode 5. Validate against pinned CPython 3.14.7; independently execute adopted source in Node and Chromium with drain and instruction-boundary drivers. Preserve core admission and the eight composed resource observations. Unsupported protocols remain explicit. No dependency, host grant, release, publication or deployment change.

Readiness: Blocked until preceding slice delivers; focused stacked work is allowed.