INT-OBJECT-01N: Specify metaclass instance and subclass checking #269

Scope

Adopt a finite CPython 3.14.7 contract and authored source corpus for metaclass instancecheck/subclasscheck, actual-type shortcuts, implicit metaclass lookup, descriptor binding, result truth conversion, native type defaults, tuple short-circuit/error ordering and explicit refusal boundaries. Wire reference and independent Node/Chromium drain/step reports; keep implementation stages disabled until delivered.

Dependencies and acceptance

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

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: Ready.