[zumbrunn]

Slice 2 of the @dune/plugin-api extraction (duneorg/dune#64). Stacked on #13 (slice 1); base is that branch. Draft until #12, #13 and core 0.36 are out.

Uses services.engines and services.authz from core (duneorg/dune slice 2) instead of building the engines itself:

• mod.ts no longer calls createWorkflowEngine, createScheduler, createStagingEngine, createMachineTranslator or new AuditLogger, and no longer imports bootstrapAdminTuples; admin tuples are seeded with services.authz.seedAdminTuples().
• The audit/MT setup block in setup() is replaced by reading api.services.engines.
• executeScheduledAction stays here.

Tests and deno task check pass (237) against unreleased core 0.36 (scratch workspace). Not mergeable until @dune/core is bumped to ^0.36.0.

🤖 Generated with Claude Code

[zumbrunn]

Landed in 4.0.0 as part of #26 (one squash of the whole stack: its intermediate commits only type-check against the final contract). Verified against the published @dune/core 0.36.0 and @dune/testing 2.0.0.