feat(fusion_login_audit): settings model + page section

Four x_fc_* fields on res.config.settings backed by ir.config_parameter:
retention_days (default 365, 0 = forever), alert_threshold (5),
alert_window_min (15), alert_enabled (True). New "Login Audit" block
on the General Settings page (gated by base.group_system on the block,
NOT on the inherited view record per CLAUDE.md rule #11).

CLAUDE.md gotchas added during this task:
  #5 Boolean config_parameter fields don't round-trip "False" as a
     string — IrConfigParameter.set_param deletes the row on falsy.
     Test with assertFalse, never assertEqual(..., "False").
  #6 ir.ui.view uses group_ids (Odoo 19 rename mirrored from res.users).
     Setting groups_id on an ir.ui.view record raises ValueError at
     install. (The XML attribute groups="..." on inner nodes is
     unrelated and still works.)

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

fusion_login_audit/tests/test_login_audit.py

@@ -266,3 +266,21 @@ class TestFusionLoginAuditModel(TransactionCase):
         self.assertEqual(action['type'], 'ir.actions.act_window')
         # Domain must filter to this user
         self.assertIn(('user_id', '=', user.id), action['domain'])
+
+    def test_settings_round_trip(self):
+        """Writing settings persists them via ir.config_parameter."""
+        Settings = self.env['res.config.settings'].sudo()
+        Settings.create({
+            'x_fc_login_audit_retention_days': 90,
+            'x_fc_login_audit_alert_threshold': 3,
+            'x_fc_login_audit_alert_window_min': 5,
+            'x_fc_login_audit_alert_enabled': False,
+        }).execute()
+        ICP = self.env['ir.config_parameter'].sudo()
+        self.assertEqual(ICP.get_param('fusion_login_audit.retention_days'), '90')
+        self.assertEqual(ICP.get_param('fusion_login_audit.alert_threshold'), '3')
+        self.assertEqual(ICP.get_param('fusion_login_audit.alert_window_min'), '5')
+        # Odoo's set_param deletes the row when the value is falsy, so a
+        # Boolean field set to False yields get_param() == False (Python
+        # bool, the default), not the string 'False'.
+        self.assertFalse(ICP.get_param('fusion_login_audit.alert_enabled'))