fix(pos): resolve integration test failures for CFDI + accounting

- Fix sat_accounts.sql: split multi-row INSERT into individual statements
  so parent_id subqueries resolve correctly (was producing all NULLs)
- Add tenant_config table to v1.0 schema (required by CFDI invoicing)
- Seed tenant_config with RFC/regimen during tenant provisioning
- Fix cancel_sale to pass complete sale data for accounting reversal
- Fix CFDI XML builder: use `or` instead of dict.get() defaults to
  handle explicit None values from DB (clave_prod_serv, clave_unidad)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pos/services/pos_engine.py

@@ -481,14 +481,19 @@ def cancel_sale(conn, sale_id, reason):
 
     # Reverse accounting entry (non-blocking)
     try:
-        # Fetch tax_total for the reversal entry
-        cur.execute("SELECT tax_total FROM sales WHERE id = %s", (sale_id,))
-        _tax_row = cur.fetchone()
-        record_cancellation_entry(conn, {
-            'id': sale_id,
-            'total': float(s_total),
-            'tax_total': float(_tax_row[0]) if _tax_row else 0.0,
-        })
+        # Fetch full sale data for the reversal entry
+        cur.execute("""SELECT subtotal, tax_total, total, sale_type, payment_method
+                       FROM sales WHERE id = %s""", (sale_id,))
+        _sale_row = cur.fetchone()
+        if _sale_row:
+            record_cancellation_entry(conn, {
+                'id': sale_id,
+                'subtotal': float(_sale_row[0]) if _sale_row[0] else 0.0,
+                'tax_total': float(_sale_row[1]) if _sale_row[1] else 0.0,
+                'total': float(_sale_row[2]) if _sale_row[2] else 0.0,
+                'sale_type': _sale_row[3] or 'cash',
+                'payment_method': _sale_row[4] or 'efectivo',
+            })
     except Exception:
         pass  # Accounting errors never block cancellations