test canonical ABI conformance

[JairusSW]

Summary

• port Wasmtime canonical ABI string-boundary and post-return regressions
• route canonical-option lifts through the graph path and execute zero-argument post-return functions
• preserve canonical adapter traps as component call errors
• run guest resource destructors without calling synthetic host exports directly

Why

The optimized component path discarded canonical options, zero-stack calls could skip required post-return work, adapter validation traps escaped as panics, and resource destruction stopped at a synthetic host export. These gaps prevented upstream conformance cases and real guest-owned resources from working safely.

Validation

• go test ./...