feat(panel): adaptive monitoring poll intervals (v1.x closure phase 1)

Replace fixed 5 s hx-trigger polling with data-poll markers and panel.js
scheduling: 5 s while active, 30 s when idle, none when tab is hidden.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

internal/web/templates/deliveries_rows.html

@@ -1,6 +1,6 @@
 {{define "deliveries_rows"}}
-<div id="deliveries-rows" hx-get="/deliveries/rows?domain={{.FilterDomain}}&app={{.FilterApp}}&p={{.Page}}"
-     hx-trigger="every 5s" hx-swap="outerHTML">
+<div id="deliveries-rows" data-poll hx-get="/deliveries/rows?domain={{.FilterDomain}}&app={{.FilterApp}}&p={{.Page}}"
+     hx-trigger="load" hx-swap="outerHTML">
   {{if .Rows}}
   <table>
     <thead>

internal/web/templates/mail_queue_body.html

@@ -1,5 +1,5 @@
 {{define "mail_queue_body"}}
-<div id="mail-queue-body" hx-get="/mail-queue/body" hx-trigger="every 5s" hx-swap="outerHTML">
+<div id="mail-queue-body" data-poll hx-get="/mail-queue/body" hx-trigger="load" hx-swap="outerHTML">
   {{if .Error}}<p class="error">{{.Error}}</p>{{end}}
   <span class="code">{{if .Output}}{{.Output}}{{else}}Queue is empty.{{end}}</span>
 </div>

internal/web/templates/status.html

@@ -44,7 +44,7 @@
 
 {{/* The status page's section index, shown in the navigation column (see the
      "sections" block in layout.html). The first six cards are the ones the
-     polling fragment replaces every five seconds; their ids are part of
+     polling fragment replaces on a timer; their ids are part of
      status_body.html and do not change with the reading, so the links here hold
      across a refresh. */}}
 {{define "sections"}}

internal/web/templates/status_body.html

@@ -1,5 +1,5 @@
 {{define "status_body"}}
-<div id="status-body" hx-get="/status/fragment" hx-trigger="every 5s" hx-swap="outerHTML">
+<div id="status-body" data-poll hx-get="/status/fragment" hx-trigger="load" hx-swap="outerHTML">
   <div class="card" id="overall">
     <h2>Overall <span class="st st-{{.OverallStatus}}">{{.OverallStatus}}</span></h2>
     <p class="muted">{{.OverallHeading}}</p>

internal/web/templates/system_log_body.html

@@ -1,5 +1,5 @@
 {{define "system_log_body"}}
-<div id="system-log-body" hx-get="/system-log/body" hx-trigger="every 5s" hx-swap="outerHTML">
+<div id="system-log-body" data-poll hx-get="/system-log/body" hx-trigger="load" hx-swap="outerHTML">
   {{if .Error}}<p class="error">{{.Error}}</p>{{end}}
   <span class="code">{{if .Lines}}{{range .Lines}}{{.}}
 {{end}}{{else}}No log lines yet.{{end}}</span>