Improve TeleCart Pulse ETL, time handling and customer tracking

- Ensure Pulse store always prefers tracking_id from backend response when saving Telegram customer data.
- Route storeOrder calls through shared ftch helper instead of manual fetch.
- Remove legacy catalog controller extension/tgshop/handle and obsolete telecart_cache migration and setting mapping for Yandex Metrika.
- Update migrations framework to rely on Carbon, sort migration files deterministically and store executed_at as a Carbon timestamp without DEFAULT CURRENT_TIMESTAMP.
- Introduce DateUtils helper to convert timestamps between UTC and system time zone and use it in ETLHandler responses.
- Make TeleCartPulse PayloadSigner and TeleCartPulseService accept nullable secrets/API keys but fail fast when secret is missing.
- Normalize ETL customer payload shape and convert all date fields to UTC JSON timestamps.
- Default created order customer_id to 0 when no OpenCart customer id is available.

frontend/spa/src/stores/Pulse.js

@@ -37,7 +37,7 @@ export const usePulseStore = defineStore('pulse', {
                 console.debug('[Pulse] Saving Telegram customer data');
                 saveTelegramCustomer(userData)
                     .then((response) => {
-                        this.tracking_id = this.tracking_id || response?.data?.tracking_id || null;
+                        this.tracking_id = response?.data?.tracking_id || this.tracking_id || null;
                         console.debug(
                             '[Pulse] Telegram customer data saved successfully. Tracking ID: ',
                             toRaw(this.tracking_id)