Sub 17: Extract GoldenPathCoordinatorService — due/dependency trigger only, synthesizer stays as execution service

Parent Epic

#11831 — Sub 17 of Epic. Third of the 3 coordinator extractions in Discussion #11857 Cycle-3.5 B-prime convergence.

Premise

Per v13-path.md:117 D3.1 boundary, per-task coordinators decide due. GoldenPathSynthesizer currently has scheduling+dependency-gating logic in Orchestrator's scheduleGoldenPath(). Extract to coordinator.

Specific care: GoldenPathSynthesizer.synthesizeGoldenPath() is execution; stays in the synthesizer service. Coordinator owns due/dependency-trigger semantics ONLY.

Prescription

Create ai/daemons/orchestrator/services/GoldenPathCoordinatorService.mjs:

getDueTask({state, now, goldenPathIntervalMs, dependencyState, ...}) → trigger | null

The dependency-gating decision (whether a Golden-Path-dependency task like dream is currently running) is the COORDINATOR's read; the policy of what to do about it (defer + record) lives in Sub 19's MaintenanceBackpressureService.executeWithGoldenPathDependencyGate. Coordinator just returns null (not due, dependency active) OR a trigger.

Acceptance Criteria

1. ai/daemons/orchestrator/services/GoldenPathCoordinatorService.mjs ships with getDueTask({...}) only
2. Pure-function unit tests for getDueTask({...}) with synthetic state + dependency-state inputs
3. GoldenPathSynthesizer retains synthesizeGoldenPath() and all execution methods unchanged
4. Orchestrator's scheduleGoldenPath() body is NOT modified yet (Sub 18 wires)
5. Coordinator does NOT call MaintenanceBackpressureService directly — it returns advisory triggers; the gating policy is applied by Sub 18's pickNextCandidate + Sub 19's executor wrappers

Avoided Traps

• Coordinator MUST NOT absorb synthesizeGoldenPath() execution
• No reactive-config-aliased wrapper
• Dependency-gating POLICY (defer + record) is NOT in the coordinator — that's Sub 18's pickNextCandidate + Sub 19's executor

Depends on

Epic #11831.

Unblocks

Sub 18.

Authority

Discussion #11857 Cycle-3.5 graduation.

Authored by: [Claude Opus 4.7] (Claude Code)