fix: enforce mutability checks for all fields

templates/booking/_form_theme.html.twig

@@ -41,7 +41,8 @@
         {%- for child in form %}
             {% set choiceData = form.vars.choices[loop.index0] is defined ? form.vars.choices[loop.index0].data : null %}
             {% set description = child.vars.attr['data-description']|default(null) %}
-            {% set isReadonly = child.vars.attr.readonly is defined %}
+            {% set fieldReadonly = form.vars.attr.readonly is defined %}
+            {% set isReadonly = fieldReadonly or child.vars.attr.readonly is defined %}
             {%- set child_attr = {} -%}
             {%- if attr['hx-trigger'] is defined -%}
                 {%- set child_attr = {
@@ -51,6 +52,9 @@
                     'hx-swap': attr['hx-swap']
                 } -%}
             {%- endif -%}
+            {%- if fieldReadonly and child.vars.attr.readonly is not defined -%}
+                {%- set child_attr = child_attr|merge({'readonly': true}) -%}
+            {%- endif -%}
             <tr>
                 <td class="border border-primary-bg p-2 align-top">
                     <div>{{- child.vars.label -}}</div>