fix: multiline template comment and double JSON encoding in queue form

Django {# #} comments don't support multiple lines, causing raw template
text to appear in forms. The queue view double-encoded the printer map
(json.dumps + json_script), hiding all printer options in the dropdown.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: peterus

core/templates/core/includes/_form_field.html

@@ -1,7 +1,5 @@
 {% load core_tags %}
-{# Generic form field renderer.
-   Context: field — a bound Django form field.
-#}
+{% comment %}Generic form field renderer. Context: field — a bound Django form field.{% endcomment %}
 {% with widget_type=field|widget_class %}
 {% if 'HiddenInput' in widget_type %}
   {{ field }}

core/views/queue.py

@@ -93,8 +93,6 @@ def get_form(self, form_class=None):
 
     def get_context_data(self, **kwargs):
         """Add plate->compatible-printers mapping for client-side filtering."""
-        import json as _json
-
         context = super().get_context_data(**kwargs)
 
         # Build a map: plate_pk -> [compatible printer PKs]
@@ -118,7 +116,7 @@ def get_context_data(self, **kwargs):
                 compatible = [p.pk for p in printers]
             plate_printer_map[str(plate.pk)] = compatible
 
-        context["job_printer_map_json"] = _json.dumps(plate_printer_map)
+        context["job_printer_map_json"] = plate_printer_map
         return context
 
     def form_valid(self, form):