audit 4: log paging at its edges, NaN refused, a red rate limit, recalculation asks, reload writes all

Step 4 of stage 4 (L10, L11, L13, L18, L19 and a row of
review-2026-08-followups):

- The Outbound log counts first and clamps the page to the last; a number
  too large for an int (strconv's ErrRange with the largest int) is the
  last page on both logs. Tested at the edges: first, last, past the last
  however far, nonsense, an empty log asked for page 5.
- checkAutoMultiplier is "not within", so NaN and the infinities are out.
- rate-limited is red (components.go; the mockup first, 643892a).
- data-unsaved on both recalculate buttons: panel.js asks on submit
  (ev.submitter) when a field of the page differs from what it was drawn
  with; testdata/unsaved_test.js under TestPanelJS.
- HandleReload writes what a restore's first start writes - the filter
  lists and the DMARC maps too - and a failed step is an error flash on
  Health that names it, not plain text; the success flash says what was
  written.

Tested on the test server: go vet + go test of 25 packages, make e2e (all
pass, 695 s) on this tree.

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

internal/web/view/static/panel.js

@@ -99,9 +99,58 @@
     var form = ev.target.closest("form[data-confirm]");
     if (form && !window.confirm(form.dataset.confirm)) {
       ev.preventDefault();
+      return;
+    }
+    // A button that does something else than save - recalculate a rate
+    // limit - leaves the page, and what was typed on it and not saved goes
+    // with it. Such a button carries data-unsaved, the question to ask when
+    // a field of the page differs from what the page was drawn with (audit
+    // 2026-10-12, L19). HTML Living Standard, SubmitEvent: submitter is the
+    // button that submitted the form.
+    var button = ev.submitter;
+    if (button && button.dataset && button.dataset.unsaved && hasUnsavedEdit() &&
+        !window.confirm(button.dataset.unsaved)) {
+      ev.preventDefault();
     }
   });
 
+  // hasUnsavedEdit tells whether a field of the page holds a value the page
+  // was not drawn with: defaultValue, defaultChecked and defaultSelected are
+  // what the markup said (HTML Living Standard, the input, select and
+  // textarea elements). A select none of whose options says selected was
+  // drawn with its first option, or none when it is a list (size or multiple).
+  function hasUnsavedEdit() {
+    var fields = document.querySelectorAll("input, select, textarea");
+    for (var i = 0; i < fields.length; i++) {
+      var f = fields[i];
+      if (f.disabled || f.type === "hidden" || f.type === "submit" || f.type === "button" || f.type === "reset") {
+        continue;
+      }
+      if (f.type === "checkbox" || f.type === "radio") {
+        if (f.checked !== f.defaultChecked) {
+          return true;
+        }
+      } else if (f.tagName === "SELECT") {
+        var drawn = -1;
+        for (var j = 0; j < f.options.length; j++) {
+          if (f.options[j].defaultSelected) {
+            drawn = j;
+            break;
+          }
+        }
+        if (drawn < 0 && !f.multiple && f.size <= 1 && f.options.length > 0) {
+          drawn = 0;
+        }
+        if (f.selectedIndex !== drawn) {
+          return true;
+        }
+      } else if (f.value !== f.defaultValue) {
+        return true;
+      }
+    }
+    return false;
+  }
+
   // --- Conditional field visibility ------------------------------------
   // Several forms hide a block until a select, checkbox or file input says it
   // applies. One rule table drives them all so the five near-identical helpers