Add stale banner and required analysis UI

Introduces a visual indicator for stale analysis on the case page and a
new section on the "My Cases" page to highlight cases requiring
analysis. This improves user awareness of data currency and pending
actions.

server/templates/case_page.html

@@ -172,6 +172,15 @@
                 border-radius: 4px;
                 color: #842029;
             }
+            .stale-banner {
+                margin: 1em 0;
+                padding: 0.7em 1em;
+                background: #fff7e6;
+                border: 1px solid #f5a623;
+                border-radius: 4px;
+                color: #8a5a00;
+                font-size: 0.95em;
+            }
             .failure-banner strong {
                 font-size: 1.05em;
             }
@@ -495,6 +504,9 @@
         </div>
 
         {% match document_html %} {% when Some with (html) %}
+        {% if analysis_stale_with_doc %}
+        <div class="stale-banner">Analyse nicht aktuell — neue Aufnahmen seit letztem Lauf.</div>
+        {% endif %}
         <div id="doc-content" class="doc-content">
             {% if can_analyze %}
             <div class="doc-actions-top">