feat(clarification): rehydrate pending questions on reconnect + restart

A stage parked on operator clarification lost its modal whenever the
client disconnected or the server restarted — the questions were stranded
in the event log with no way to re-surface them (unlike approvals, which
already rehydrate).

Two composing mechanisms, mirroring the approval path:

- On reconnect: SessionEventBridge.replaySnapshot() now re-pushes the last
  unanswered ClarificationRequestedEvent for a PAUSED/CLARIFICATION_PENDING
  session as a ClarificationRequired message. Gated on the orchestrator
  still holding a live deferred (SessionOrchestrator.liveClarificationRequestIds)
  so a client never sees a modal whose answer could not be delivered.

- On restart: ServerModule.resumeAbandonedSessions() eagerly relaunches
  clarification-parked sessions (approval-parked stay lazy). rehydrate+resume
  re-runs the parked stage, which re-emits a fresh, live
  ClarificationRequestedEvent (round budget MAX=3, 1 prior round recorded, so
  it re-parks rather than silently proceeding), re-arming the deferred that
  the reconnect path gates on.

pauseReason == "CLARIFICATION_PENDING" is the discriminator because the
reducer sets pendingApproval=true for every pause.

core/kernel/src/main/kotlin/com/correx/core/kernel/orchestration/SessionOrchestrator.kt

@@ -312,6 +312,15 @@ abstract class SessionOrchestrator(
         ConcurrentHashMap<ClarificationRequestId, CompletableDeferred<List<ClarificationAnswer>>> =
         ConcurrentHashMap()
 
+    /**
+     * Request-ids of clarifications this process is still parked on (the [CompletableDeferred] is
+     * live and awaitable). A reconnecting client uses this to re-push only clarifications that can
+     * actually be answered — a request whose deferred died with a server restart is excluded, so the
+     * client never shows a modal that would resume nothing.
+     */
+    fun liveClarificationRequestIds(): Set<String> =
+        pendingClarifications.keys.mapTo(mutableSetOf()) { it.value }
+
     /** Cache mapping "sessionId:artifactId" to JSON-serialized artifact payload content.
      *  Populated when ProcessResult artifacts are stored on tool failure.
      *  Used by DefaultSessionOrchestrator.step() to populate EvaluationContext.artifactContent. */