feat: Connect dispatch queue to agent spawning via auto-dispatch

ExecutionOrchestrator now listens for phase:queued and agent:stopped
events to drive the dispatch cycle, closing the gap between queueing
phases (Execute button) and actually spawning agents. Coalesced
scheduling prevents reentrancy with synchronous EventEmitter.

docs/dispatch-events.md

@@ -96,3 +96,24 @@ AccountCredentialsRefreshedEvent { accountId, expiresAt, previousExpiresAt? }
 | `completePhase(phaseId)` | Mark phase complete |
 | `blockPhase(phaseId, reason)` | Block phase |
 | `getPhaseQueueState()` | Return queued, ready, blocked phases |
+
+## Auto-Dispatch (ExecutionOrchestrator)
+
+`apps/server/execution/orchestrator.ts` — Connects the queue to agent spawning via event-driven auto-dispatch.
+
+### Trigger Events
+
+| Event | Action |
+|-------|--------|
+| `phase:queued` | Dispatch ready phases → dispatch their tasks to idle agents |
+| `agent:stopped` | Re-dispatch queued tasks (freed agent slot) |
+| `task:completed` | Merge task branch, then dispatch next queued task |
+
+### Coalesced Scheduling
+
+Multiple rapid events (e.g. several `phase:queued` from `queueAllPhases`) are coalesced into a single async dispatch cycle via `scheduleDispatch()`. The cycle loops `dispatchNextPhase()` + `dispatchNext()` until both queues are drained, then re-runs if new events arrived during execution.
+
+### Execution Mode Behavior
+
+- **YOLO**: phase completes → auto-merge → auto-dispatch next phase → auto-dispatch tasks
+- **review_per_phase**: phase completes → set `pending_review` → STOP. User approves → `approveAndMergePhase()` → merge → dispatch next phase → dispatch tasks