design: the Sender check card counts connections and messages apart; ≈ for an estimate

Owner, 2026-10-14 ("Может просто показывать и то, и то и не смешивать?"):
the figure that was "Messages deferred" is two - connections Postfix turned
away while the panel did not answer (refused from the connection on, before
a message is offered), and messages deferred in the middle, when the panel
stopped answering after a message had begun (cleanup's case, counted since
the M13 fix). The card has a column for each.

The audit's stage 2b also marks a day whose downtime is an estimate - a
start at which supervisord could not say since when Postfix ran: such a
period's time is shown with ≈, and the text under the table says it is at
most what is shown.

Help: topic sender-check says what each column counts and what ≈ means;
topic log names the bounced row the panel closed itself (the sweep, when
Postfix no longer held the message and mail.log never said what became of
it). build.py, check.py: 0 violations, outlines unchanged. The code follows
in the next commits; until then the help text guard fails - not pushed in
between.

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

docs/assets/panel-redesign/panel/health.html

@@ -92,15 +92,15 @@
         <div class="box" id="sender-check">
           <div class="sp-box-head"><span class="sp-no">03</span><h2>Sender check</h2><div class="sp-end"><span class="tag is-success is-light">ok</span></div><a class="sp-help" href="help.html#sender-check" title="What is checked and what these numbers are for"><i class="ti ti-help-circle"></i></a></div>
           <div class="table-container"><table class="table is-fullwidth">
-            <thead><tr><th>Period</th><th>Panel not answering</th><th>Messages deferred</th></tr></thead>
+            <thead><tr><th>Period</th><th>Panel not answering</th><th>Connections turned away</th><th>Messages deferred</th></tr></thead>
             <tbody>
-              <tr><td>Today</td><td>0 s</td><td>0</td></tr>
-              <tr><td>Last 30 days</td><td>4 s</td><td>0</td></tr>
-              <tr><td>Last 12 months</td><td>41 s</td><td>3</td></tr>
+              <tr><td>Today</td><td>0 s</td><td>0</td><td>0</td></tr>
+              <tr><td>Last 30 days</td><td>4 s</td><td>0</td><td>0</td></tr>
+              <tr><td>Last 12 months</td><td>≈ 41 s</td><td>3</td><td>1</td></tr>
             </tbody>
           </table></div>
           <div class="sp-box-body">
-            <p class="sp-muted">The panel holds each message's <code>From:</code> against the application that sends it. While the panel does not answer, Postfix defers mail instead of accepting it unchecked. Time is counted only while Postfix itself was running. Counted since <span class="sp-mono">2026-10-13</span>.</p>
+            <p class="sp-muted">The panel holds each message's <code>From:</code> against the application that sends it. While the panel does not answer, Postfix defers mail instead of accepting it unchecked. Time is counted only while Postfix itself was running; ≈ marks a period with a start at which that could not be asked, and its time is at most what is shown. Counted since <span class="sp-mono">2026-10-13</span>.</p>
           </div>
         </div>
         <div class="box" id="hostname">