fix(migrations): make v4.3 idempotent and register all missing migrations

- Use DO block to rename xml_unsigned only if it exists
- Register all missing migrations in runner.py including v4.3

pos/migrations/v4.3_facturapi.sql

@@ -10,7 +10,15 @@
 -- ═════════════════════════════════════════════════════════════════════════════
 -- 1. CFDI_QUEUE: adapt schema for Facturapi payloads
 -- ═════════════════════════════════════════════════════════════════════════════
-ALTER TABLE cfdi_queue RENAME COLUMN xml_unsigned TO payload_unsigned;
+DO $$
+BEGIN
+    IF EXISTS (
+        SELECT 1 FROM information_schema.columns
+        WHERE table_name = 'cfdi_queue' AND column_name = 'xml_unsigned'
+    ) THEN
+        ALTER TABLE cfdi_queue RENAME COLUMN xml_unsigned TO payload_unsigned;
+    END IF;
+END $$;
 
 COMMENT ON COLUMN cfdi_queue.payload_unsigned IS 'Facturapi JSON payload (previously unsigned XML for Horux)';
 COMMENT ON COLUMN cfdi_queue.xml_signed IS 'Signed+stamped XML returned by Facturapi';