feat: publish a standalone configurable Rhai runtime capsule

Outcome

Publish a standalone configurable Rhai runtime capsule that AOS agents and users can use for recipes, automation, and surface behavior.

Scope and ownership

Create a dedicated unicity-aos/capsule-rhai repository and installable capsule. Expose a language-neutral script-runtime contract to callers. Interpreter feature profiles and limits are configurable only within immutable host-granted ceilings. Named profiles and stricter limit requests are principal- and request-bound; they are validated from governed invocation/configuration data, never cached globally or sourced from ambient environment variables.

Dependencies

• Astrid SDK and capsule build/install path.
• Generic execution containment evidence from the Astrid substrate campaign.

Exit gate

The capsule evaluates bounded scripts, receives only granted bus and host capabilities, supports named profiles, exposes deterministic errors and cancellation, produces an installable artifact, and passes runaway CPU/memory/recursion/output adversarial tests. Scripts may request stricter settings but cannot widen features, capabilities, or ceilings.

Claim boundary

The capsule does not authorize effects, replace Astrid policy, provide arbitrary native code, or make scripts trusted.

Verification

Default and restricted profile corpus, principal/config isolation, capability-denial tests, cancellation/restart tests, deterministic serialization tests, installability proof, and cross-version fixture compatibility.