Fix session resume: auto-open most advanced sub-session on parent click

When reopening a parent session that has page-split sub-sessions,
the UI was showing the parent's pipeline step (always step 1/Orientation)
instead of navigating to the sub-sessions. Now automatically opens the
most advanced sub-session, matching the behavior of handleOrientationComplete.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

admin-lehrer/app/(admin)/ai/ocr-pipeline/page.tsx

@@ -73,6 +73,12 @@ export default function OcrPipelinePage() {
       if (data.sub_sessions && data.sub_sessions.length > 0) {
         setSubSessions(data.sub_sessions)
         setParentSessionId(sid)
+        // Parent has sub-sessions — open the most advanced one automatically
+        const sorted = [...data.sub_sessions].sort(
+          (a: SubSession, b: SubSession) => (b.current_step || 0) - (a.current_step || 0),
+        )
+        openSession(sorted[0].id, true)
+        return
       } else if (data.parent_session_id) {
         // This is a sub-session — keep parent info but don't reset sub-session list
         setParentSessionId(data.parent_session_id)