refactor: use english for routes, parameters and internal messages

templates/board/_calendar.html.twig

@@ -2,14 +2,14 @@
    requests whose response carries nothing but out-of-band blocks, hence hx-swap="none". #}
 {% set weekdays = ['Mo', 'Di', 'Mi', 'Do', 'Fr', 'Sa', 'So'] %}
 {# Every link keeps the board's span, so changing the day never silently widens it back to all-day. #}
-{% set time_params = selected_time.allDay ? {} : { von: selected_time.start, bis: selected_time.end } %}
+{% set time_params = selected_time.allDay ? {} : { from: selected_time.start, to: selected_time.end } %}
 
 <div class="rounded-md border border-gray-200 p-4">
     <div class="flex items-center justify-between pb-4">
         <button type="button"
                 class="p-1 rounded-md hover:bg-gray-100"
                 aria-label="Voriger Monat"
-                hx-get="{{ path('app_board_day', { type: type.slug, date: month_start|date_modify('-1 month')|date('Y-m-d') }|merge(time_params)) }}"
+                hx-get="{{ path('app_board_day', { type: type.value, date: month_start|date_modify('-1 month')|date('Y-m-d') }|merge(time_params)) }}"
                 hx-swap="none">
             {{ ux_icon('lucide:chevron-left', { class: 'w-5 h-5' }) }}
         </button>
@@ -19,7 +19,7 @@
         <button type="button"
                 class="p-1 rounded-md hover:bg-gray-100"
                 aria-label="Nächster Monat"
-                hx-get="{{ path('app_board_day', { type: type.slug, date: month_start|date_modify('+1 month')|date('Y-m-d') }|merge(time_params)) }}"
+                hx-get="{{ path('app_board_day', { type: type.value, date: month_start|date_modify('+1 month')|date('Y-m-d') }|merge(time_params)) }}"
                 hx-swap="none">
             {{ ux_icon('lucide:chevron-right', { class: 'w-5 h-5' }) }}
         </button>
@@ -49,7 +49,7 @@
                 <button type="button"
                         class="{{ classes }}"
                         aria-pressed="{{ day.is_selected ? 'true' : 'false' }}"
-                        hx-get="{{ path('app_board_day', { type: type.slug, date: day.date|date('Y-m-d') }|merge(time_params)) }}"
+                        hx-get="{{ path('app_board_day', { type: type.value, date: day.date|date('Y-m-d') }|merge(time_params)) }}"
                         hx-swap="none">
                     <span>{{ day.date|date('j') }}</span>
                     {# Team view: the occupancy count is the whole point of showing the month. #}