Analytics: compare two finished runs

New page /analytics/compare and API GET /admin/analytics/compare (+ /lists/{group}):
the administrator picks an old (A) and a new (B) run; the report shows the new
addresses (only in B), the ones that left (only in A) and the common ones whose
membership in the seven indicators (pass, partial, fail, egress https any/all,
ingress ssh any/all) differs, with a "what changed" summary per address; the
dynamics of each indicator (delta = new - left + entered - exited) and a verdict
transition matrix. Every number opens a list with CSV. Cancelled addresses are not
part of a run. The list dialog moved to a shared analytics-dialog.js and template;
/analytics got a "compare with another run" button.

Docs, plan and summary in docs/changes/.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

internal/dashboard/templates/analytics.html

@@ -19,6 +19,7 @@
 </div>
 {{if .HasRun}}
 <script type="application/json" id="analytics-data">{{.DataJSON}}</script>
+<script src="/static/analytics-dialog.js"></script>
 <script src="/static/analytics.js"></script>
 {{end}}
 </body>
@@ -46,6 +47,7 @@
 {{end}}
 </select>
 {{if .NextURL}}<a class="an-btn" href="{{.NextURL}}" aria-label="Следующий запуск">▶</a>{{else}}<span class="an-btn" aria-disabled="true" style="opacity:.4">▶</span>{{end}}
+{{if .HasRun}}<a class="an-btn" href="/analytics/compare?target={{.RunID}}">Сравнить с другим запуском</a>{{end}}
 </div>
 {{if .HasRun}}<p class="an-note" id="an-runnote"></p>{{else}}<p class="an-note">Завершённых запусков пока нет: данные появятся, когда все адреса запуска получат итог.</p>{{end}}
 </section>
@@ -114,23 +116,7 @@
 <p class="an-note">Ровная полоса значит: проблема зависит от подсети адреса, а не от валидатора.</p>
 </section>
 
-<dialog id="an-dlg" aria-labelledby="an-dlg-title">
-<div class="an-dlg">
-<h3 id="an-dlg-title"></h3>
-<p class="an-note" id="an-dlg-note"></p>
-<div class="an-dist" id="an-dlg-dist" hidden></div>
-<div class="an-list"><table id="an-dlg-tbl"></table></div>
-<div class="an-foot">
-<span class="an-note" id="an-dlg-msg" role="status"></span>
-<div class="an-acts">
-<button class="an-btn" type="button" id="an-dlg-copy">Копировать</button>
-<button class="an-btn an-primary" type="button" id="an-dlg-csv">Скачать CSV</button>
-<button class="an-btn" type="button" id="an-dlg-close" autofocus>Закрыть</button>
-</div>
-</div>
-</div>
-</dialog>
-<div id="an-tip" role="tooltip"></div>
+{{template "analytics_dialog"}}
 {{end}}
 </div>
 {{end}}