Refactor AI analysis and email fetching functionality

- Removed AI analysis guide and related documentation files.
- Updated email fetching logic to intelligently determine start date based on the latest email date in the database.
- Enhanced the app module to include a button for re-analyzing threads with AI.
- Improved database interactions to trigger AI analysis after ingesting sent emails.
- Adjusted the UI to display additional information about threads, including formatted latest message dates.
- Removed outdated test scripts for AI analysis and email fetching.
- Updated styles for better responsiveness and layout in the frontend.

templates/thread_detail.html

@@ -12,6 +12,9 @@
           <span class="badge success">Up to date</span>
         {% endif %}
       </p>
+      <div class="mt-2">
+        <a href="/thread/{{ thread.id }}?force_analyze=true" class="btn btn-sm">🔄 Re-analyze with AI</a>
+      </div>
     </div>
   </div>
 
@@ -19,14 +22,22 @@
     <div class="col">
       <div class="card">
         <h3>AI Analysis</h3>
-        <p>
-          <strong>Actionable:</strong>
-          {% if ai.actionable %}<span class="badge warn">Yes</span>{% else %}<span class="badge success">No</span>{% endif %}
-        </p>
-  <p><strong>Summary:</strong> {{ ai.summary or thread.ai_summary }}</p>
-        <p class="muted">Confidence: {{ ai.confidence }} • Model: {{ ai.model }}</p>
-  <p class="muted">Last stored: {{ thread.last_analyzed_at }}</p>
-  <p class="muted">Last alert level sent: {{ thread.last_alert_level_sent }} at {{ thread.last_alert_sent_at }}</p>
+        {% if ai %}
+          <p>
+            <strong>Actionable:</strong>
+            {% if ai.actionable %}<span class="badge warn">Yes</span>{% else %}<span class="badge success">No</span>{% endif %}
+          </p>
+          <p><strong>Summary:</strong> {{ ai.summary or "No summary available" }}</p>
+          <p class="muted">Confidence: {{ ai.confidence or "N/A" }}{% if ai.model %} • Model: {{ ai.model }}{% endif %}</p>
+          {% if ai.analyzed_at %}
+            <p class="muted">Analysis cached from: {{ ai.analyzed_at }}</p>
+          {% elif thread.last_analyzed_at %}
+            <p class="muted">Last analyzed: {{ thread.last_analyzed_at }}</p>
+          {% endif %}
+        {% else %}
+          <p class="muted">No AI analysis available</p>
+        {% endif %}
+        <p class="muted">Last alert level sent: {{ thread.last_alert_level_sent }}{% if thread.last_alert_sent_at %} at {{ thread.last_alert_sent_at }}{% endif %}</p>
       </div>
     </div>
   </div>