Introduce notifications app and integrate emails

Add a new notifications app (models, serializers, views, admin, tasks, consumers, routing, urls, tests) with Notification.notify for in-app websocket pushes and optional email delivery. Centralize email sending in notifications.tasks.send_email_with_context and re-export it from account.tasks for compatibility. Update account and commerce and advertisement tasks to use Notification.notify/_notify_order and the new email helper; adjust order/notification tasks to consolidate logic. Wire notifications into ASGI routing, settings and URL conf. Misc: handle OSError when importing weasyprint, add tmp/ to .gitignore, add local .claude PowerShell checks, add social.blog skeleton, and remove legacy ews-component test files.

backend/notifications/tasks.py

@@ -0,0 +1,119 @@
+from datetime import datetime
+
+from celery import shared_task
+from celery.utils.log import get_task_logger
+
+from django.core.mail import send_mail, EmailMultiAlternatives
+
+logger = get_task_logger(__name__)
+
+from account.models import CustomUser
+from django.conf import settings
+from django.template.loader import render_to_string
+
+
+@shared_task
+def send_notification_email_task(recipient_email, subject, template_path, context=None, attachments=None):
+    send_email_with_context(
+        recipients=recipient_email,
+        subject=subject,
+        template_path=template_path,
+        context=context or {},
+        attachments=attachments,
+    )
+
+
+
+def send_email_with_context(recipients, subject, template_path=None, context=None, message: str | None = None, attachments=None):
+    """
+    Send email using component-based template system.
+    Uses base.html with header/footer components and includes the specified content template.
+    """
+    if isinstance(recipients, str):
+        recipients = [recipients]
+
+    if not recipients:
+        logger.warning("No recipients provided for email. Skipping sending email.")
+        return "No recipients provided for email."
+    
+    ctx = dict(context or {})
+    
+    # Add current_year to context if not present
+    if "current_year" not in ctx:
+        ctx["current_year"] = datetime.now().year
+    
+    # Add AppConfig data for footer if not already present
+    if "company_name" not in ctx:
+        try:
+            from configuration.models import AppConfig
+            config = AppConfig.objects.first()
+            if config:
+                ctx["company_name"] = config.company_name
+                ctx["company_address"] = config.company_address
+                ctx["company_ico"] = config.company_ico
+                ctx["company_dic"] = config.company_dic
+                ctx["contact_email"] = config.contact_email
+                ctx["contact_phone"] = config.contact_phone
+        except Exception:
+            pass  # Gracefully skip if AppConfig not available
+    
+    # Sanitize user if someone passes the model by mistake
+    if "user" in ctx and not isinstance(ctx["user"], dict):
+        try:
+            ctx["user"] = _build_user_template_ctx(ctx["user"])
+        except Exception:
+            ctx["user"] = {}
+
+    # Render HTML using base template with content include
+    html_message = None
+    if template_path:
+        ctx["content_template"] = template_path
+        html_message = render_to_string("email/components/base.html", ctx)
+
+    try:
+        email = EmailMultiAlternatives(
+            subject=subject,
+            body=message or "Tento e-mail vyžaduje HTML podporu.",
+            from_email=None,
+            to=recipients if len(recipients) == 1 else [],
+            bcc=recipients if len(recipients) > 1 else [],
+        )
+        
+        if html_message:
+            email.attach_alternative(html_message, "text/html")
+        
+        if attachments:
+            for filename, content, mimetype in attachments:
+                email.attach(filename, content, mimetype)
+        
+        email.send(fail_silently=False)
+        
+        logger.info(f"Sent email to {recipients} with subject '{subject}'")
+
+        if settings.EMAIL_BACKEND == 'django.core.mail.backends.console.EmailBackend':
+            logger.debug(f"\nEMAIL HTML:\n{html_message}\nKONEC OBSAHU")
+        return "Successfully sent email."
+    except Exception as e:
+        logger.error(f"E-mail se neodeslal: {e}")
+        raise  # Re-raise so Celery marks the task as FAILED and can retry
+
+
+def _build_user_template_ctx(user: CustomUser) -> dict:
+    """
+    Return a plain dict for templates instead of passing the DB model.
+    Provides aliases to avoid template errors (firstname vs first_name).
+    Adds a backward-compatible key 'get_full_name' for templates using user.get_full_name.
+    """
+    first_name = getattr(user, "first_name", "") or ""
+    last_name = getattr(user, "last_name", "") or ""
+    full_name = f"{first_name} {last_name}".strip()
+    return {
+        "id": user.pk,
+        "email": getattr(user, "email", "") or "",
+        "first_name": first_name,
+        "firstname": first_name,   # alias for templates using `firstname`
+        "last_name": last_name,
+        "lastname": last_name,     # alias for templates using `lastname`
+        "full_name": full_name,
+        "get_full_name": full_name,  # compatibility for templates using method-style access
+    }