Add IP search and status filter to the Overview and Registry dashboard pages

Both pages rendered their full lists with no way to narrow them. Adds a
?q=&status= filter (substring match on address, exact match on result
status) applied dashboard-side, in Go, over the already-fetched list —
no control-api/db changes needed.

Overview: the filter form lives outside the polling target (#overview-live)
so the recurring poll never wipes out what's typed/selected; the poll and
both filter inputs share hx-sync="#overview-live:queue last" (the same
fix that resolved the earlier abandoned /ips auto-refresh races) and the
poll now carries hx-include="#overview-filter" so it keeps honoring the
current filter on every tick. Applies uniformly to both the "Текущая
проверка" and "Последние N завершённых" tables, per the confirmed design:
picking a specific status naturally hides in-progress rows, since they
have no result yet.

Registry: no polling exists there, so the filter form reuses the full page
via hx-select/hx-replace-url — simpler than adding a parallel fragment
endpoint, and gives a bookmarkable/shareable filtered URL.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

internal/dashboard/templates/overview.html

@@ -23,7 +23,36 @@
 <div class="topbar">
 <h1>Обзор</h1>
 </div>
-<div id="overview-live" hx-get="/overview/fragment" hx-trigger="every {{.PollSeconds}}s" hx-swap="innerHTML">
+
+<form id="overview-filter" class="panel" onsubmit="return false">
+<div class="panel-body field-row">
+<div class="field" style="flex:1 1 260px">
+<label for="overview-q">Поиск по IP</label>
+<input type="search" id="overview-q" name="q" value="{{.Query}}" placeholder="203.0.113.10"
+  hx-get="/overview/fragment" hx-target="#overview-live" hx-swap="innerHTML"
+  hx-include="#overview-filter" hx-trigger="input changed delay:300ms"
+  hx-sync="#overview-live:queue last">
+</div>
+<div class="field">
+<label for="overview-status">Статус</label>
+<select id="overview-status" name="status"
+  hx-get="/overview/fragment" hx-target="#overview-live" hx-swap="innerHTML"
+  hx-include="#overview-filter" hx-trigger="change" hx-sync="#overview-live:queue last">
+<option value="">Все</option>
+<option value="pass" {{if eq .StatusFilter "pass"}}selected{{end}}>pass</option>
+<option value="partial" {{if eq .StatusFilter "partial"}}selected{{end}}>partial</option>
+<option value="fail" {{if eq .StatusFilter "fail"}}selected{{end}}>fail</option>
+<option value="cancelled" {{if eq .StatusFilter "cancelled"}}selected{{end}}>cancelled</option>
+</select>
+</div>
+</div>
+<p class="muted" style="padding:0 16px 12px">Действует на обе таблицы ниже. Фильтр по статусу — это фильтр по
+итоговому результату, поэтому при выборе конкретного статуса строки «Текущей проверки» (у неё ещё нет результата)
+не показываются.</p>
+</form>
+
+<div id="overview-live" hx-get="/overview/fragment" hx-trigger="every {{.PollSeconds}}s"
+  hx-include="#overview-filter" hx-sync="#overview-live:queue last" hx-swap="innerHTML">
 {{template "overview_fragment" .}}
 </div>
 {{end}}