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/tenant_manager.py

@@ -165,6 +165,18 @@ def provision_tenant(name, rfc=None, owner_name="Admin", owner_email=None, owner
             (owner_id, perm)
         )
 
+    # Seed tenant_config with RFC and defaults
+    if rfc:
+        tenant_cur.execute("""
+            INSERT INTO tenant_config (key, value) VALUES
+            ('tenant_rfc', %s),
+            ('tenant_razon_social', %s),
+            ('tenant_cp', '00000'),
+            ('cfdi_regimen_fiscal', '601'),
+            ('cfdi_serie', 'A')
+            ON CONFLICT (key) DO NOTHING
+        """, (rfc, name))
+
     tenant_conn.commit()
     tenant_cur.close()
     tenant_conn.close()