fix(billing): name ledger partners by company, not the NexaCloud user's full_name

One operator (e.g. "Gurpreet Singh") manages several distinct customer
businesses; naming partners from full_name mislabeled Mobility Specialties
Inc and Apex Vita Corporation as "Gurpreet Singh". Read the company field,
name the partner by company (mark is_company), and rewrite existing partners
so prior full_name-based names are corrected on re-ingest. 75 tests green.

fusion_centralize_billing/tests/test_invoice_ledger.py

@@ -120,6 +120,14 @@ class TestLedgerIngest(TransactionCase):
         self.assertAlmostEqual(mv.amount_untaxed, 200.0, places=2)  # captured via reconciling line
         self.assertTrue(any('base/unitemized' in (l.name or '') for l in mv.invoice_line_ids))
 
+    def test_partner_named_by_company_not_person(self):
+        data = _inv_fixture()
+        data[0]['partner_company'] = 'Acme Holdings Inc'  # full_name is "Acme"; company wins
+        self.W._ingest_invoices(data, post=False)
+        mv = self.Move.search([('x_fc_nexacloud_invoice_id', '=', 'inv-1')])
+        self.assertEqual(mv.partner_id.name, 'Acme Holdings Inc')
+        self.assertTrue(mv.partner_id.is_company)
+
     def test_prune_shadow_removes_shadow_subs_only(self):
         p = self.env['res.partner'].sudo().create({'name': 'X'})
         shadow = self.env['sale.order'].sudo().create({'partner_id': p.id, 'x_fc_shadow': True})