refactor(ui): move detail drawer chrome to a server-rendered partial

The drawer chrome used to be built in JS via a 50-line innerHTML string
and needed every caller to plumb through a labels object sourced from
per-page PHP config. That diverged from the codebase convention — the
confirm dialog, search dialog and session warning are all PHP partials
mounted once in templates/default.phtml. The drawer now follows the
same pattern: templates/partials/app-detail-drawer.phtml renders the
markup with t() labels, default.phtml mounts it inside the logged-in
shell, and the JS only attaches behavior via the [data-detail-drawer]
selector.

Knock-on cleanup: ensureDrawerElement and resolveLabels disappear from
the JS, all three initDetailDrawer callers (admin/users, address book,
helpdesk debitor) drop their labels parameter, and the matching dead
'drawerClose'/'drawerPrev'/… entries leave the per-page PHP grid configs.
The drawer also gains a clean fallback when the partial is missing
(console warn + null return), so logged-out edges can't crash.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

templates/default.phtml

@@ -340,6 +340,7 @@ $componentPageConfig['moduleRuntimeComponents'] = $moduleRuntimeComponents;
   <?php if ($isLoggedIn): ?>
   <?php require __DIR__ . '/partials/app-search-dialog.phtml'; ?>
   <?php require __DIR__ . '/partials/app-session-warning-dialog.phtml'; ?>
+  <?php require __DIR__ . '/partials/app-detail-drawer.phtml'; ?>
   <?php endif; ?>
   <?php foreach ($moduleBodyEndTemplateSlots as $slot): ?>
     <?php

templates/partials/app-detail-drawer.phtml

@@ -0,0 +1,57 @@
+<?php
+
+/**
+ * Shared right-edge detail drawer.
+ *
+ * Mounted once at the bottom of the logged-in shell so admin list pages
+ * can attach behavior via [data-detail-drawer]. Markup mirrors what
+ * web/js/components/app-detail-drawer.js drives — JS only queries
+ * data-attributes, never injects chrome.
+ */
+
+?>
+<div class="app-detail-drawer"
+  data-detail-drawer
+  role="dialog"
+  aria-modal="true"
+  aria-hidden="true"
+  hidden>
+  <div class="app-detail-drawer-backdrop" data-detail-drawer-backdrop></div>
+  <aside class="app-detail-drawer-panel" data-detail-drawer-panel tabindex="-1">
+    <header class="app-detail-drawer-header">
+      <div class="app-detail-drawer-stepper">
+        <button type="button" class="transparent icon-button" data-detail-drawer-prev
+          aria-label="<?php e(t('Previous')); ?>"
+          data-tooltip="<?php e(t('Previous')); ?>"
+          data-tooltip-pos="bottom">
+          <i class="bi bi-chevron-left"></i>
+        </button>
+        <button type="button" class="transparent icon-button" data-detail-drawer-next
+          aria-label="<?php e(t('Next')); ?>"
+          data-tooltip="<?php e(t('Next')); ?>"
+          data-tooltip-pos="bottom">
+          <i class="bi bi-chevron-right"></i>
+        </button>
+      </div>
+      <div class="app-detail-drawer-actions">
+        <a role="button" class="secondary outline small app-detail-drawer-full"
+          data-detail-drawer-full
+          aria-label="<?php e(t('Open full page')); ?>">
+          <i class="bi bi-box-arrow-up-right" aria-hidden="true"></i>
+          <span><?php e(t('Open full page')); ?></span>
+        </a>
+        <button type="button" class="transparent icon-button" data-detail-drawer-close
+          aria-label="<?php e(t('Close')); ?>"
+          data-tooltip="<?php e(t('Close')); ?>"
+          data-tooltip-pos="bottom">
+          <i class="bi bi-x-lg"></i>
+        </button>
+      </div>
+    </header>
+    <div class="app-detail-drawer-body" data-detail-drawer-body>
+      <div class="app-detail-drawer-loading" data-detail-drawer-loading hidden><?php e(t('Loading')); ?></div>
+      <div class="app-detail-drawer-error" data-detail-drawer-error hidden><?php e(t('Failed to load')); ?></div>
+      <div class="app-detail-drawer-content" data-detail-drawer-content></div>
+    </div>
+  </aside>
+</div>