Add integration tests covering the price-drop → Telegram alert flow:
- Sends Telegram MarkdownV2 message to global SiteSettings chat_id when
detected price <= watcher.alert_price_threshold.
- No alert when global creds missing.
- No alert when price above threshold.
- No alert when threshold unset on watcher.
- Non-recurring watcher with an undismissed alert is not re-notified.
- Telegram API failure does not break the check (snapshot + alert row
still persist, last_price updates).
AlertsPartialView (htmx-polled every 30s from the dashboard) returned
500 because _alerts.html used {% trans %} without {% load i18n %}.
Added the load tag so the partial renders correctly.
The dashboard's inline {% include 'pricemon/_alerts.html' %} also
relied on an undefined 'alerts' context var (DashboardView sets
'active_alerts'), so the alerts panel rendered empty even when alerts
existed. Pass alerts=active_alerts explicitly via the include.
Add regression tests covering both the dashboard render with an alert
and the alerts partial endpoint.