feat(aircoding): AirCoding V2 baseline — deterministic multi-agent architecture

Forked from OpenCode v1.17.4 with multi-agent system:
- 5 agents: aircoding, scheduler, worker, architect, reviewer
- Deterministic DAG scheduling engine (coordinator_tick)
- Tool whitelists as hard enforcement
- AirCoding validation plugin
- V1 requirements: C4 docs, ADR, AGENTS.md, debug-log.md
- Design documents in docs/

packages/opencode/src/background/job.ts

@@ -0,0 +1,39 @@
+import { LayerNode } from "@opencode-ai/core/effect/layer-node"
+import { BackgroundJob as CoreBackgroundJob } from "@opencode-ai/core/background-job"
+import { InstanceState } from "@/effect/instance-state"
+import { Effect, Layer } from "effect"
+
+export {
+  Service,
+  type ExtendInput,
+  type Info,
+  type Interface,
+  type StartInput,
+  type Status,
+  type WaitInput,
+  type WaitResult,
+} from "@opencode-ai/core/background-job"
+
+/** Keeps the legacy service instance-scoped while sharing the core registry engine. */
+export const layer = Layer.effect(
+  CoreBackgroundJob.Service,
+  Effect.gen(function* () {
+    const state = yield* InstanceState.make(() => CoreBackgroundJob.make)
+    return CoreBackgroundJob.Service.of({
+      list: () => InstanceState.useEffect(state, (jobs) => jobs.list()),
+      get: (id) => InstanceState.useEffect(state, (jobs) => jobs.get(id)),
+      start: (input) => InstanceState.useEffect(state, (jobs) => jobs.start(input)),
+      extend: (input) => InstanceState.useEffect(state, (jobs) => jobs.extend(input)),
+      wait: (input) => InstanceState.useEffect(state, (jobs) => jobs.wait(input)),
+      waitForPromotion: (id) => InstanceState.useEffect(state, (jobs) => jobs.waitForPromotion(id)),
+      promote: (id) => InstanceState.useEffect(state, (jobs) => jobs.promote(id)),
+      cancel: (id) => InstanceState.useEffect(state, (jobs) => jobs.cancel(id)),
+    })
+  }),
+)
+
+export const defaultLayer = layer
+
+export const node = LayerNode.make(layer, [])
+
+export * as BackgroundJob from "./job"