Developer onboarding fixes - devcontainer, vscode, cargo-about

[dzil123]

Some minor fixes to issues I ran into using devcontainer on this project with vscode.

• Add esbenp.prettier-vscode to the recommended extensions list as it's already used in .vscode/settings.json
• Install wasm32-unknown-unknown Rust target in devcontainer
• Add cargo-binstall and pin cargo-about version in devcontainer
• Remove no-clearly-defined = true from about.toml:
  • cargo-about 0.9.1 fails to run if no-clearly-defined is present
  • cargo-about 0.8.0 already removed support for clearlydefined.io, so the argument is a no-op

[cubic-dev-ai]

All reported issues were addressed across 4 files

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