Add RRULE humanizer and wire events into nodes#showerdgeist-revive-events

- app/models/concerns/rrule_humanizer.rb: new concern included into
  Event, renders recurring schedule as natural-language German or
  English from RRULE string; handles WEEKLY/MONTHLY, biweekly
  (INTERVAL=2), ordinal weekday positions (1TU, -1TH, -2WE),
  BYMONTH single-month exclusions (December pause convention);
  gracefully returns nil for COUNT/UNTIL/unrecognized shapes
- test/models/concerns/rrule_humanizer_test.rb: 15 tests covering
  all distinct RRULE shapes found in production data
- app/helpers/nodes_helper.rb: add event_schedule_text helper
  combining humanize_rrule with start_time formatting
- app/views/nodes/show.html.erb: add events row, conditionally
  rendered when node has associated events
- config/locales/de.yml, en.yml: add event_schedule_time,
  event_schedule_unrecognized, event_schedule_none keys

1 files changed, 13 insertions, 1 deletions

diff --git a/app/views/nodes/show.html.erb b/app/views/nodes/show.html.erb
index de4d8a2..7223219 100644
--- a/app/views/nodes/show.html.erb
+++ b/app/views/nodes/show.html.erb
@@ -42,6 +42,18 @@
       <td class="description">Tagged with:</td>
       <td><%= @page.tag_list %></td>
     </tr>
+    <% if @node.events.any? %>
+    <tr>
+      <td class="description">Events</td>
+      <td>
+        <ul>
+        <% @node.events.order(:start_time).each do |event| %>
+          <li><%= event_schedule_text(event) %><%= " (primary)" if event.is_primary? %></li>
+        <% end %>
+        </ul>
+      </td>
+    </tr>
+    <% end %>
     <tr>
       <td class="description"><strong>Title</strong></td>
       <td><%= sanitize( @page.title ) %></td>
@@ -59,4 +71,4 @@
       <td class="right"></td>
     </tr>
   </table>
-</div>
\ No newline at end of file
+</div>