Refactor case detail into a dedicated page

This commit restructures the web interface for case details. The
previous `/web/cases/{case_id}` route, which previously showed both the
case summary and its recordings, has been split into two distinct pages:

- `/web/cases/{case_id}`: This page now displays the overall case
  information, including the document if available.
- `/web/cases/{case_id}/recordings`: This new page is dedicated to
  listing and displaying individual recordings within a case.

This change improves the organization and clarity of the web UI,
allowing for more focused views of case data. Additionally, the
`case_detail.html` and `document.html` templates have been removed as
their functionality is now handled by the new `case_page.html` and the
upcoming document rendering logic. The `cases.html` template has also
been removed, indicating a shift towards more granular page views.

server/templates/my_cases.html

@@ -67,7 +67,7 @@ section h2 { font-size: 1.1em; color: #555; border-bottom: 1px solid #ddd; paddi
 <li class="case-row {% if case.has_document %}done{% else %}open{% endif %}">
 <div class="check"><input type="checkbox" name="case_id" value="{{ case.case_id }}"></div>
 <div class="body">
-{% if case.has_document %}<a href="/web/cases/{{ case.case_id }}/document">{% else %}<a href="/web/cases/{{ case.case_id }}">{% endif %}
+<a href="/web/cases/{{ case.case_id }}">
 <div class="line1"><span class="time"><time datetime="{{ case.recorded_at_iso }}">{{ case.time_hms_utc }}</time></span>{% match case.oneliner %}{% when Some with (t) %} — {{ t }}{% when None %} — <span class="empty">kein Oneliner</span>{% endmatch %}</div>
 <div class="line2">{{ case.recordings_count }} Aufnahmen{% if case.has_document %} — <span class="status-badge done">ausgewertet</span>{% else %} — <span class="status-badge open">offen</span>{% endif %}{% if case.analyzing %} <span class="label analyzing">wird analysiert</span>{% endif %}</div>
 {% if is_admin %}<div class="uuid">{{ case.case_id }}</div>{% endif %}