Apple: ship public Swift embedder SDK for iOS and macOS clients

[enricopiovesan]

Summary

Ship the public Swift embedder SDK required by reference-apps #114.

Depends on

• Spec 068 approval.

Definition of Done

• Versioned Swift Package exposes every Spec 068 embedder operation, including compatible-capability start/stop/kill, with stable Swift-facing types.
• It loads bundled runtime/manifests/capabilities and has no production dependency on traverse-cli serve.
• It forwards runtime-owned output, state, and structured errors without UI/business-rule duplication.
• It includes public API docs, compatibility policy, and deterministic test double.
• It passes shared conformance plus iOS/macOS package tests.
• iOS and macOS reference-app integration executes a bundled workflow without a sidecar.
• Release evidence records package version, runtime-WASM digest, and conformance version.

Unblocks

• reference-apps Specify AI agent execution and WASM agent packaging slice #114 after Template executable capability package manifests and deterministic build commands #111 and Document adapter responsibilities versus core runtime responsibilities #112 are also complete.

[enricopiovesan]

Unblocked (2026-07-13): Spec 068 was approved and merged in PR #651. This implementation ticket is now Ready.

[enricopiovesan]

Blocked after pre-flight (2026-07-13): this ticket explicitly depends on Spec 068 approval, but current main contains no specs/068-* artifact and no approved-spec registry entry for 068. The available embedder governing material is Spec 057, which does not define the requested versioned public SDK contract or release evidence.

Unblock by landing and approving Spec 068 (including the public Swift API, runtime-WASM packaging/digest, conformance version, and compatibility commitments), then return this item to Ready.

[enricopiovesan]

Board correction (2026-07-13): Spec 068 is approved and present on main via PR #651. The earlier blocker report was stale. This ticket is Ready; its Definition of Done now correctly cites Spec 068 and the complete embedder lifecycle.