feat(platform): add phase5 runtime persistence e2e readiness

[ActiveInAI]

Summary

Adds Phase 5 runtime persistence E2E readiness across backend contracts, smoke scripts, frontend API Lab, OpenAPI examples, and handoff docs.

Scope

• Hardens artifact/job/registry pagination and invariant contracts.
• Tightens viewer command status transitions and audit behavior.
• Expands backend contract tests for generated artifacts, status mirroring, registry policies, and viewer command kinds.
• Updates OpenAPI runtime/artifact/viewer/registry examples while preserving valid SDK generation.
• Improves /app/dev/api-lab runtime status, IDs, and error visibility.
• Strengthens smoke scripts with ARCHITOKEN_API_BASE_URL, jq checks, and clearer assertions.
• Adds Phase 5 handoff documentation.

Validation

• cargo fmt --all -- --check
• cargo clippy --all-targets --all-features -- -D warnings
• cargo test --all-targets --all-features
• cargo build --release --bin insomeos-gateway
• npx --yes @redocly/cli@2.30.0 lint openapi.yaml
• npx --yes @openapitools/openapi-generator-cli@2.23.0 generate -i openapi.yaml -g typescript-fetch -o /tmp/architoken-sdk-ts
• ./scripts/smoke-all.sh
• bun run lint
• bun run typecheck
• bun run test
• bun run build
• git diff --check

OpenAPI

Redocly passes with 1 existing localhost dev server warning.

Boundary

Still mock/in-memory/dev persistence boundary. No real model, no DB migration, no infra change, no proprietary loader/SDK/EXE.