Squash-merge of feat/helpdesk-customer-followup. The billing and
fusion_login_audit work from that branch is already on main (landed
separately); this lands only the helpdesk feature.
- Identity keystone: submit() forwards partner_email/partner_name/
x_fc_client_label so the central Helpdesk find-or-creates the customer
partner and subscribes them as a follower (enables reply emails + magic link).
- Embedded in-app 'My Tickets' inbox: server-side scoped read/reply RPC
endpoints, per-user seen tracking (fusion.helpdesk.ticket.seen), systray
unread badge. Defense-in-depth scope domain + _norm_email normalisation
(wildcard emails cannot widen scope).
- fusion_helpdesk_central: x_fc_client_label field + list/search views +
branded acknowledgement email template.
- Deployed and smoke-tested live: nexa central 19.0.1.1.0, entech client
19.0.1.4.1 (requires Contact Creation on the central service account).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
6c15a7b1cf