Reports: 30 business reports in 6 categories (financial, participants, attendance,
enrollments, operations, inventory) with CSV export. New ReportsHub grid page and
generic ReportViewer with date/branch filters.

Fixes: refund now creates double-entry transaction + deducts from cash session,
branch switcher properly persists "all branches" selection, trainer wizard
compensation step reactive, gender display on edit, participant edit supports
national_id and guardian phone, participant list shows membership column + searches
by national_id/membership_id.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>