Every page header's Refresh button rendered a downward chevron because
the icon set had no refresh glyph. Added a circular-arrow 'refresh'
icon to UiIcon and pointed all seven Refresh buttons (Overview,
Tenants, Partners, Users, Operator team, Audit, Infrastructure) at it.
- Partners list with name/domain/status/customers/margin + Create modal
- Partner detail: contract card, contact card, customers table, attach modal,
terminate (soft-delete) danger card
- Operator proxies for /partners + /partners/:slug/tenants
- platform-api: add partnerId Prop to Tenant schema. The field was being
silently dropped by Mongoose because the schema didn't declare it.
- tenants.service: rewrite update() to build $set/$unset explicitly and cast
partnerId via new Types.ObjectId(). Handles detach via $unset so the field
vanishes from the doc cleanly.