feat: CSV data export and scheduled reports

[c0dewhacker]

Summary

The analytics routes provide good dashboards, but enterprises need to export data to their own BI tools (Power BI, Tableau, Looker).

Proposed Solution

• CSV export button on every analytics view (utilisation, bookings by day, top users, floor utilisation)
• CSV export on the booking report page (/bookings/report)
• API: Accept: text/csv header on analytics endpoints to return CSV instead of JSON
• Scheduled email reports: weekly utilisation summary sent to Super Admins
• API key / service account authentication for headless data extraction (for BI tool integration)
• Consider adding an /api/v1/analytics/export endpoint with date range + format params

Priority

🟡 P2 — Medium impact, low effort

[c0dewhacker]

Implementation plan

• CSV export (minor, do first): honour Accept: text/csv on the analytics endpoints + /bookings/report, and add GET /analytics/export?from&to&format. Stream CSV, reusing the existing query builders.
• Scheduled reports / service accounts (larger): weekly summary via a pg-boss job + email; headless API-key auth for BI tools — recommend tracking separately.
• Effort: export small; the rest medium.

[c0dewhacker]

Status check: the client-side slice is already done — apps/web/src/pages/admin/ReportsAdminPage.tsx has downloadCsv() and per-section export buttons (booking activity, zone utilisation, etc.), so admins can export analytics to CSV from the UI today.

Remaining scope for this issue:

• Server-side export: honour Accept: text/csv on the analytics endpoints + a GET /analytics/export?from&to&format (for BI tools / headless use)
• Scheduled reports (pg-boss job + email) and service-account/API-key auth — larger; worth splitting out.