feat(fusion_helpdesk): identity keystone helpers, seen model, admin group

Phase 1-2: build_ticket_vals/scope/unread helpers (utils.py), fusion.helpdesk.ticket.seen read-tracking model, group_reporter_admin. 10 unit tests pass on local Community.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

fusion_helpdesk/tests/test_seen.py

@@ -0,0 +1,27 @@
+# -*- coding: utf-8 -*-
+# Copyright 2026 Nexa Systems Inc.
+# License OPL-1
+"""Tests for fusion.helpdesk.ticket.seen read-tracking."""
+from odoo.tests import TransactionCase, tagged
+
+
+@tagged('post_install', '-at_install', 'fusion_helpdesk')
+class TestSeen(TransactionCase):
+
+    def test_mark_seen_upserts_and_is_monotonic(self):
+        Seen = self.env['fusion.helpdesk.ticket.seen']
+        Seen._mark_seen(central_ticket_id=42, last_message_id=100)
+        Seen._mark_seen(central_ticket_id=42, last_message_id=120)
+        Seen._mark_seen(central_ticket_id=42, last_message_id=90)   # stale, ignored
+        rec = Seen.search([
+            ('user_id', '=', self.env.uid),
+            ('central_ticket_id', '=', 42),
+        ])
+        self.assertEqual(len(rec), 1, "should upsert, not duplicate")
+        self.assertEqual(rec.last_seen_message_id, 120, "monotonic — never moves back")
+
+    def test_seen_map(self):
+        Seen = self.env['fusion.helpdesk.ticket.seen']
+        Seen._mark_seen(1, 10)
+        Seen._mark_seen(2, 20)
+        self.assertEqual(Seen._seen_map([1, 2, 3]), {1: 10, 2: 20})