feat(fusion_helpdesk): owner-approval engagement flow + AI summary + reporting

Ships the design spec at docs/superpowers/specs/2026-05-27-owner-approval-flow-design.md.

What's new on central (fusion_helpdesk_central 19.0.1.2.0 -> 19.0.2.0.0):

- Engagement model: 8 new fields on helpdesk.ticket (state, snapshotted
  owner email/name, single-use UUID4 token, sent/reminded/decided
  timestamps, AI summary, stored-computed turnaround hours).
- Wizard: single + bulk modes on one fusion.helpdesk.engagement.wizard
  TransientModel with a child wizard.line for per-ticket bulk summaries.
  default_get pulls the OpenAI summary on open; AI fan-out for bulk is
  parallel via ThreadPoolExecutor (max 5 workers, 30s overall cap).
- OpenAI client in utils.py — stdlib urllib, 15s per-call timeout, every
  failure collapses to '' so the wizard's manual-summary fallback fires.
- Public portal: /fusion_helpdesk/engagement/<token>/<decision> GET +
  POST, four branded standalone QWeb pages (confirm/done/invalid/error).
  Token is single-use, cleared on confirm. Decision posts a public
  comment attributed to the resolved owner partner; chatter propagates
  to the employee's My Tickets thread per the "fully visible" UX choice.
- Mail templates (single + bulk) with magic-link buttons. Bulk template
  renders one card per ticket, each with its own approve/reject URL.
- Reminder cron: daily, single-shot per engagement, configurable via
  fusion_helpdesk_central.engagement_reminder_days ICP (default 3, 0
  disables).
- Reporting dashboard: pivot/graph/list/kanban over helpdesk.ticket
  filtered to engaged ones, with avg-turnaround measure. Menu lives
  under Helpdesk > Reporting > Owner Engagements.
- Client_key extended with owner_email/owner_name fields; ticket.create
  upserts them from the client-side piggyback (no new sync endpoint).
- 100% coverage on utils + integration tests on wizard, controllers,
  re-engagement, cron, computed turnaround. OpenAI mocked in CI.

What's new on client (fusion_helpdesk 19.0.1.7.1 -> 19.0.2.0.0):

- Two new ICP settings: fusion_helpdesk.owner_email / .owner_name with
  a new "Owner Approval" block in Settings > Fusion Helpdesk.
- controllers/main.py::submit piggybacks both keys on every ticket
  payload so central keeps client_key.owner_email/name fresh
  automatically.

Verified live end-to-end on entech -> nexa: payload upsert, wizard with
mocked AI, action_send, portal GET/POST/GET-again cycle, second click
hits the friendly invalid-token page. Token entropy = 122 bits (UUID4).

fusion_helpdesk/models/res_config_settings.py

@@ -50,3 +50,22 @@ class ResConfigSettings(models.TransientModel):
              'can tell which client deployment a ticket came from. '
              'e.g. "ENTECH" → "[ENTECH] My subject"',
     )
+    # Owner contact for the central engagement / approval flow. Optional —
+    # leaving these blank disables the "Request Owner Approval" button on
+    # the central side for this client. Both values piggyback on every
+    # ticket submission (see controllers/main.py::submit) so central always
+    # has the latest contact without a dedicated sync endpoint.
+    fhd_owner_email = fields.Char(
+        string='Owner Email',
+        config_parameter='fusion_helpdesk.owner_email',
+        help='Email of the real decision-maker at your company — the '
+             'person who can approve feature requests or bug-fix scope. '
+             'Used when central support hits a ticket that needs sign-off. '
+             'Leave blank if your deployment doesn\'t require approvals.',
+    )
+    fhd_owner_name = fields.Char(
+        string='Owner Name',
+        config_parameter='fusion_helpdesk.owner_name',
+        help='Display name for the owner — shown in the approval email '
+             'greeting and in the chatter attribution after they decide.',
+    )