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_central/data/ir_cron_engagement_reminder.xml

@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+    Copyright 2026 Nexa Systems Inc.
+    License OPL-1
+
+    Single-shot reminder cron for the owner-approval engagement flow.
+    Runs once a day; for each pending engagement older than N days that
+    hasn't been reminded yet, re-sends the same template with
+    is_reminder=True (different subject + soft "still waiting" intro,
+    same magic links). Sets reminded_at so we never send a 2nd reminder.
+
+    Odoo 19: no `numbercall` field (dropped). The cron keeps running
+    while active=True; once-a-day cadence is enforced by interval_*.
+-->
+<odoo>
+    <data noupdate="1">
+
+        <record id="ir_cron_engagement_reminder" model="ir.cron">
+            <field name="name">Fusion Helpdesk — Owner Engagement Reminder</field>
+            <field name="model_id" ref="helpdesk.model_helpdesk_ticket"/>
+            <field name="state">code</field>
+            <field name="code">model._fc_send_engagement_reminders()</field>
+            <field name="user_id" ref="base.user_root"/>
+            <field name="interval_number">1</field>
+            <field name="interval_type">days</field>
+            <field name="active" eval="True"/>
+        </record>
+
+    </data>
+</odoo>