Rename the Export stage to Finish

It now holds files, sharing, handouts, slides, importing notes, schedule,
co-teachers and earlier versions, not just exports.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/components/SessionSchedule.jsx

@@ -1,4 +1,4 @@
-// Export → Schedule: the study's sessions (one per chunk) as a calendar file, starting on a date you pick.
+// Finish → Schedule: the study's sessions (one per chunk) as a calendar file, starting on a date you pick.
 import { useState } from 'react';
 import { formatChunkReference } from '../utils/bibleUtils.jsx';
 import { buildIcs, downloadIcs, sessionDates } from '../utils/icsFile.js';