feat(vm): freeze builtin call IDs

[fffonion]

Summary

• assign every VM-visible builtin an explicit immutable u16 call index
• validate duplicate, missing, stale, and out-of-range catalog entries at build time
• keep the checked-in pd-vm-nostd ID mirror synchronized with the standard catalog
• use static IDs across bytecode validation, VMBC, AOT artifacts, debugger recordings, and native dispatch
• document the reserved ordinary and special-call ID blocks

Scope

This branch is based directly on master and contains only the static builtin ID work. Host signature inference, HTTP, lifecycle, capability, and async-driver changes are excluded.

Validation

• cargo fmt --all -- --check
• cargo test --locked --workspace
• cargo test --locked --workspace --all-features
• cargo clippy --locked --workspace --all-targets -- -D warnings
• cargo clippy --locked --workspace --all-targets --all-features -- -D warnings