fix: array-table boolean columns always saved as unchecked (#381)

Reported bug: countdown plugin always shows "No Active" even with a
countdown configured and enabled — because every save silently unchecked
it. Root cause: the boolean column's hidden-sentinel input (needed so
unchecked checkboxes still submit "false", since browsers omit unchecked
checkboxes entirely) was hardcoded to value="false" and shared the same
`name` as the checkbox, with no sync between them. Whichever of the two
same-named inputs the save request's form-collection happens to prefer,
the hidden's stale "false" could silently override an actually-checked
box on every save, independent of what the user set.

Fixed in both places this pattern is rendered:
- plugin_config.html: the initial server-rendered row for every array-table
  boolean column (affects countdown's per-countdown "enabled" and the
  custom-feeds widget's per-feed "enabled") — now sets the hidden's initial
  value from the actual data, and syncs it via onchange on every toggle.
- array-table.js: the client-side row renderer used when adding/rebuilding
  rows in the browser — same fix, keeping both inputs in sync at render
  time and via a change listener.

Verified other checkbox/hidden-input patterns in plugin_config.html and
confirmed they're unrelated/already-safe: the default single-checkbox
renderer (no hidden pair), checkbox-group (array-bracket names with its
own explicit sync), the array-table advanced-props modal editor (single
hidden per name, explicitly written on Save), the top-level plugin
enable/disable toggle (separate immediate hx-post), and the no-schema
fallback checkbox. custom-feeds.js's own client-side row renderer never
creates a hidden sentinel at all, so it isn't affected either.

Verified the fix's rendered output directly with an isolated Jinja render
of the exact snippet: hidden and checkbox now agree ("true"/checked or
"false"/unchecked) for both states, where before the hidden was always
"false" regardless of the actual value.


Claude-Session: https://claude.ai/code/session_01KEZK1P1Q1fu5pcuVrkrCFZ

Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>

web_interface/static/v3/js/widgets/array-table.js

@@ -174,11 +174,16 @@
         cell.style.verticalAlign = 'middle';
 
         if (colType === 'boolean') {
-            // Boolean: hidden sentinel + visible checkbox
+            // Boolean: hidden sentinel + visible checkbox, same `name` (so
+            // unchecked boxes still submit "false"). Keep the hidden's value
+            // synced to the checkbox at all times — some form-collection
+            // paths prefer whichever of the two same-named inputs comes
+            // first/last in the DOM, and a stale hidden value previously
+            // caused this field to silently revert to false on every save.
             const hidden = document.createElement('input');
             hidden.type  = 'hidden';
             hidden.name  = inputName;
-            hidden.value = 'false';
+            hidden.value = String(Boolean(colValue));
             cell.appendChild(hidden);
 
             const cb = document.createElement('input');
@@ -187,6 +192,9 @@
             cb.checked   = Boolean(colValue);
             cb.value     = 'true';
             cb.className = 'h-4 w-4 text-blue-600';
+            cb.addEventListener('change', () => {
+                hidden.value = String(cb.checked);
+            });
             cell.appendChild(cb);
 
         } else if (colType === 'integer' || colType === 'number') {

web_interface/templates/v3/partials/plugin_config.html

@@ -450,15 +450,16 @@
                                             </div>
                                         </td>
                                         <td class="px-4 py-3 whitespace-nowrap text-center">
-                                            <input type="hidden" name="{{ full_key }}.{{ item_index }}.enabled" value="false">
+                                            <input type="hidden" name="{{ full_key }}.{{ item_index }}.enabled" value="{{ 'true' if item.get('enabled', true) else 'false' }}">
-                                            <input type="checkbox" 
+                                            <input type="checkbox"
                                                    name="{{ full_key }}.{{ item_index }}.enabled"
                                                    {% if item.get('enabled', true) %}checked{% endif %}
                                                    value="true"
+                                                   onchange="this.previousElementSibling.value = this.checked ? 'true' : 'false'"
                                                    class="h-4 w-4 text-blue-600">
                                         </td>
                                         <td class="px-4 py-3 whitespace-nowrap text-center">
-                                            <button type="button" 
+                                            <button type="button"
                                                     onclick="removeCustomFeedRow(this)"
                                                     class="text-red-600 hover:text-red-800 px-2 py-1">
                                                 <i class="fas fa-trash"></i>
@@ -549,11 +550,18 @@
                                         {% else %}{% set td_min_w = '110px' %}{% endif %}
                                         <td class="px-3 py-3 whitespace-nowrap" style="min-width:{{ td_min_w }};vertical-align:middle">
                                             {% if col_type == 'boolean' %}
-                                                <input type="hidden" name="{{ full_key }}.{{ item_index }}.{{ col_name }}" value="false">
+                                                {# Hidden sentinel ensures unchecked boxes still submit "false" (browsers
+                                                   omit unchecked checkboxes entirely). It shares the checkbox's `name`,
+                                                   so it must always mirror the checkbox's actual state — both here at
+                                                   render time and on every toggle — or whichever of the two same-named
+                                                   inputs the save request happens to prefer can silently revert this
+                                                   field to false regardless of what's checked. #}
+                                                <input type="hidden" name="{{ full_key }}.{{ item_index }}.{{ col_name }}" value="{{ 'true' if col_value else 'false' }}">
                                                 <input type="checkbox"
                                                        name="{{ full_key }}.{{ item_index }}.{{ col_name }}"
                                                        {% if col_value %}checked{% endif %}
                                                        value="true"
+                                                       onchange="this.previousElementSibling.value = this.checked ? 'true' : 'false'"
                                                        class="h-4 w-4 text-blue-600">
                                             {% elif col_type == 'integer' or col_type == 'number' %}
                                                 <input type="number"