fix: implement dynamic import.defer() using evaluate_for_import_defer
Use the new V8 Module::evaluate_for_import_defer API for dynamic
import.defer() to properly gather async transitive dependencies before
resolving. Get the deferred namespace via get_module_namespace_with_phase
(kDefer) so V8 creates a namespace that triggers evaluation on first
property access.
Handles three promise states:
- Fulfilled: all async deps ready, resolve immediately with deferred ns
- Rejected: propagate error to dynamic import reject
- Pending: store for later resolution via pending_dyn_mod_evaluations
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>