feat: StarlingMonkey upgrade

[TartanLlama]

• Bumps wasi-sdk to v30 from v20
• Bumps rustc to 1.88 from 1.81
• Moves from the old NPM wizer package to pulling down wasmtime and using the version of wizer bundled with wasmtime
• Uses the new policy-based way of defining finalizable builtins
• Stubs out parts of AbortSignal and AbortController that are usid in other places in StarlingMonkey
• Fixes compiler diagnostics that are triggered based on the wasi-sdk bump
• Fixes misplaced namespace in fastly.h
• Removes the now-unnecessary copy of rust-toolchain.toml
• Updates wpt expectations

Docs still todo

[TartanLlama]

@zkat can you suggest what docs changes would be required for the SPKI and PKCS8 support?