fix: аудит — 19 фиксов безопасности, надёжности, UI и 16 новых тестов

- S4: bump jinja2>=3.1.4, python-multipart>=0.0.18, httpx>=0.28.0
- S5: _detect_ecosystem — DEFAULT_ECOSYSTEM для неизвестных форматов
- S6: harvester — log.exception() вместо log.error()
- S8: _scan_component — urlencode параметров
- P1: scanner — proc.kill() при таймауте
- P3: api_packages — selectinload(Scan.findings), убран N+1
- P4+P5: утечка _url_locks и _llm_locks при early return
- P6: DB reaper — сброс {'status':'analyzing'} при старте
- UI: htmx-пагинация, фильтры не теряют flagged, 404 с layout
- UI: мобильные таблицы overflow-x, полная стата на дашборде
- UI: i18n статусов в _status_badge, urlencode package_name
- 16 новых тестов: analyze endpoint (6), scanner errors (4),
  webhook signature (2), llm client (4)

guarddog_nexus/web/templates/dashboard_stats.html

@@ -1,10 +1,24 @@
 {% if total_findings %}
-<div style="display:flex; gap:1.5rem; padding:0.3rem 0; margin-bottom:1rem; border-bottom:1px solid var(--pico-color-gray-500); font-size:0.82rem; opacity:0.8;">
+<div style="display:flex; gap:1.5rem; padding:0.3rem 0; margin-bottom:1rem; border-bottom:1px solid var(--pico-color-gray-500); font-size:0.82rem; opacity:0.8; flex-wrap:wrap;">
+    <span>{{ t('total_scans_label', request.state.lang) }}: <strong>{{ total_scans }}</strong></span>
+    <span>{{ t('flagged_scans_label', request.state.lang) }}: <strong>{{ flagged_scans }}</strong></span>
     <span>{{ t('col_findings', request.state.lang) }}: <strong>{{ total_findings }}</strong></span>
     <span>{{ t('llm_analyzed', request.state.lang) }}: <strong>{{ llm_analyzed }}</strong></span>
     <span>{{ t('llm_pending', request.state.lang) }}: <strong>{{ llm_pending }}</strong></span>
 </div>
 {% endif %}
+{% if top_rules %}
+<article class="dash-block" style="margin-bottom:1rem;">
+    <h3>{{ t('heading_top_rules', request.state.lang) }}</h3>
+    <table class="compact">
+        <tbody>
+        {% for r in top_rules %}
+            <tr><td><strong>{{ r.rule }}</strong></td><td>{{ r.count }}</td></tr>
+        {% endfor %}
+        </tbody>
+    </table>
+</article>
+{% endif %}
 {% if latest_flagged %}
 <article class="dash-block dash-block-warn">
     <h3>{{ t('heading_latest_flagged', request.state.lang) }}</h3>