feat(fusion_helpdesk_central): expose OpenAI key + cron settings in UI

Adding the 'Fusion Helpdesk Central' block to General Settings so the
three ICP keys the engagement flow reads are configurable from a real
form instead of forcing admins to open Technical → System Parameters.

Three settings, all wired via config_parameter= so the existing read
paths (engagement_wizard, _fc_send_engagement_reminders) keep working
unchanged:

- fusion_helpdesk_central.openai_api_key (password widget — doesn't
  render plaintext on the form)
- fusion_helpdesk_central.openai_model (default 'gpt-4o-mini')
- fusion_helpdesk_central.engagement_reminder_days (default 3, 0
  disables the reminder cron entirely)

Bumps fusion_helpdesk_central to 19.0.2.2.0.

Find under Settings → Fusion Helpdesk Central. The block has two
sub-sections: "Owner Approval — AI Summary" (key + model) and
"Owner Approval — Reminder Cadence" (days).

fusion_helpdesk_central/__manifest__.py

@@ -3,7 +3,7 @@
 # License OPL-1
 {
     'name': 'Fusion Helpdesk Central — Client API Keys',
-    'version': '19.0.2.1.0',
+    'version': '19.0.2.2.0',
     'category': 'Productivity',
     'summary': 'Admin UI on the central Odoo for issuing per-client API '
                'keys used by fusion_helpdesk client deployments.',
@@ -37,6 +37,7 @@ Depends only on `helpdesk`. No client-side install needed.
         'views/engagement_wizard_views.xml',
         'views/engagement_reporting_views.xml',
         'views/portal_templates.xml',
+        'views/res_config_settings_views.xml',
     ],
     'installable': True,
     'auto_install': False,

fusion_helpdesk_central/models/__init__.py

@@ -2,3 +2,4 @@
 from . import fusion_helpdesk_client_key
 from . import helpdesk_ticket
 from . import engagement_wizard
+from . import res_config_settings

fusion_helpdesk_central/models/res_config_settings.py

@@ -0,0 +1,45 @@
+# -*- coding: utf-8 -*-
+# Copyright 2026 Nexa Systems Inc.
+# License OPL-1
+"""Settings for fusion_helpdesk_central exposed via General Settings.
+
+Surfaces the three ICP keys the engagement flow reads — OpenAI key /
+model / reminder cadence — so admins don't have to dig into Technical →
+System Parameters to set up the AI summary or change the reminder
+window. All three are stored in ir.config_parameter via the
+`config_parameter=` shortcut so the existing read paths
+(engagement_wizard, helpdesk_ticket._fc_send_engagement_reminders)
+continue to work unchanged.
+"""
+from odoo import fields, models
+
+
+class ResConfigSettings(models.TransientModel):
+    _inherit = 'res.config.settings'
+
+    fhc_openai_api_key = fields.Char(
+        string='OpenAI API Key',
+        config_parameter='fusion_helpdesk_central.openai_api_key',
+        help='Server-side key the engagement wizard uses to generate AI '
+             'summaries on Engage. Leave blank to disable AI summaries — '
+             'the wizard still works, you just write the brief manually. '
+             'Keep secret: anyone with access to System Parameters could '
+             'read it back.',
+    )
+    fhc_openai_model = fields.Char(
+        string='OpenAI Model',
+        config_parameter='fusion_helpdesk_central.openai_model',
+        default='gpt-4o-mini',
+        help='OpenAI model used for the engagement summary. Default '
+             'gpt-4o-mini balances cost and quality — switch to gpt-4o '
+             'or gpt-4o-2024-08-06 if you find summaries too thin.',
+    )
+    fhc_engagement_reminder_days = fields.Integer(
+        string='Reminder After (days)',
+        config_parameter='fusion_helpdesk_central.engagement_reminder_days',
+        default=3,
+        help='Days of inaction before the cron sends a single follow-up '
+             'reminder to the owner. Set to 0 to disable reminders '
+             'entirely. The cron sends at most one reminder per '
+             'engagement regardless of this value.',
+    )

fusion_helpdesk_central/views/res_config_settings_views.xml

@@ -0,0 +1,52 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+    Copyright 2026 Nexa Systems Inc.
+    License OPL-1
+
+    General Settings → Fusion Helpdesk Central. Surfaces the three ICP
+    keys that drive the engagement flow's AI summary + reminder cron.
+    Password widget on the API key so it doesn't render in plaintext on
+    the settings form (still recoverable via System Parameters, but at
+    least it's not over-the-shoulder visible).
+-->
+<odoo>
+
+    <record id="res_config_settings_view_form_fhc" model="ir.ui.view">
+        <field name="name">res.config.settings.view.form.fusion.helpdesk.central</field>
+        <field name="model">res.config.settings</field>
+        <field name="inherit_id" ref="base.res_config_settings_view_form"/>
+        <field name="arch" type="xml">
+            <xpath expr="//form" position="inside">
+                <app data-string="Fusion Helpdesk Central"
+                     string="Fusion Helpdesk Central"
+                     name="fusion_helpdesk_central">
+                    <block title="Owner Approval — AI Summary"
+                           name="fhc_openai">
+                        <setting id="fhc_openai_api_key"
+                                 string="OpenAI API Key"
+                                 help="Used by the 'Request Owner Approval' wizard to auto-generate the brief shown to the owner. Leave blank to disable AI summary — the wizard still works, you write the brief manually.">
+                            <field name="fhc_openai_api_key"
+                                   password="True"
+                                   placeholder="sk-…"/>
+                        </setting>
+                        <setting id="fhc_openai_model"
+                                 string="OpenAI Model"
+                                 help="Default gpt-4o-mini is cheap (~$0.15/M input tokens) and fast. Bump to gpt-4o if summaries are too thin.">
+                            <field name="fhc_openai_model"
+                                   placeholder="gpt-4o-mini"/>
+                        </setting>
+                    </block>
+                    <block title="Owner Approval — Reminder Cadence"
+                           name="fhc_reminder">
+                        <setting id="fhc_engagement_reminder_days"
+                                 string="Send reminder after (days)"
+                                 help="Days the cron waits before sending a single follow-up reminder on a pending engagement. 0 disables reminders. The cron sends AT MOST ONE reminder per engagement regardless of value — re-engaging the same ticket resets the clock.">
+                            <field name="fhc_engagement_reminder_days"/>
+                        </setting>
+                    </block>
+                </app>
+            </xpath>
+        </field>
+    </record>
+
+</odoo>