feat(aria): group Device Posture table by institution with collapsible accordion

All institutions expanded by default. Header row shows device count,
avg posture score, and a warning badge when any device scores below 80.
Fetches all records in one call (size=500) instead of paginating.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/components/DevicePosture.svelte

@@ -2,14 +2,9 @@
   import { onMount, onDestroy } from 'svelte';
   import { ariaApi, type DeviceSecurityPosture, type OsEolStatus } from '../lib/api';
   import { addToast } from '../lib/stores';
-  import Pagination from './common/Pagination.svelte';
 
   let postures: DeviceSecurityPosture[] = [];
   let totalElements = 0;
-  let totalPages = 0;
-  let currentPage = 0;
-  let pageSize = 25;
-
   let loading = true;
 
   // Filter sidebar
@@ -23,18 +18,62 @@
   let panelOpen = false;
   let panelDevice: DeviceSecurityPosture | null = null;
 
-  async function load(page = 0) {
+  // Accordion — all expanded by default
+  let expandedInstitutions = new Set<string>();
+  let allLoaded = false;
+
+  interface InstGroup {
+    key: string;
+    devices: DeviceSecurityPosture[];
+    avgScore: number | null;
+    hasIssues: boolean;
+  }
+
+  $: grouped = groupByInstitution(postures);
+
+  function groupByInstitution(list: DeviceSecurityPosture[]): InstGroup[] {
+    const map = new Map<string, DeviceSecurityPosture[]>();
+    for (const d of list) {
+      const k = d.institutionKey ?? 'Unknown';
+      if (!map.has(k)) map.set(k, []);
+      map.get(k)!.push(d);
+    }
+    return Array.from(map.entries())
+      .sort((a, b) => a[0].localeCompare(b[0]))
+      .map(([key, devices]) => {
+        const scored = devices.filter(d => d.postureScore != null);
+        const avgScore = scored.length
+          ? Math.round(scored.reduce((s, d) => s + d.postureScore!, 0) / scored.length)
+          : null;
+        const hasIssues = devices.some(d => d.postureScore != null && d.postureScore < 80);
+        return { key, devices, avgScore, hasIssues };
+      });
+  }
+
+  function toggleInstitution(key: string) {
+    if (expandedInstitutions.has(key)) {
+      expandedInstitutions.delete(key);
+    } else {
+      expandedInstitutions.add(key);
+    }
+    expandedInstitutions = expandedInstitutions;
+  }
+
+  async function load() {
     loading = true;
     try {
-      const params: Record<string, any> = { page, size: pageSize };
+      const params: Record<string, any> = { page: 0, size: 500 };
       if (filterScore) params.scoreFilter = filterScore;
       if (filterEol)   params.osEolStatus = filterEol;
 
       const res = await ariaApi.getPostures(params);
       postures = res.data.content;
       totalElements = res.data.page.totalElements;
-      totalPages = res.data.page.totalPages;
-      currentPage = res.data.page.number;
+
+      if (!allLoaded) {
+        expandedInstitutions = new Set(postures.map(d => d.institutionKey ?? 'Unknown'));
+        allLoaded = true;
+      }
     } catch {
       addToast('error', 'Load Failed', 'Could not load device posture data');
     } finally {
@@ -45,8 +84,7 @@
   function clearAllFilters() {
     filterScore = '';
     filterEol = '';
-    currentPage = 0;
-    load(0);
+    load();
   }
 
   function openPanel(device: DeviceSecurityPosture) {
@@ -105,13 +143,13 @@
 
   async function doRefresh() {
     refreshing = true;
-    await load(currentPage);
+    await load();
     refreshing = false;
     secondsLeft = REFRESH_SECONDS;
   }
 
   onMount(() => {
-    load(0);
+    load();
     tickInterval = setInterval(() => {
       if (!autoRefreshEnabled) return;
       if (secondsLeft > 1) {
@@ -193,7 +231,7 @@
           <div class="filter-section">
             <label class="filter-section-label">Score</label>
             <select class="filter-select" bind:value={filterScore}
-              on:change={() => { currentPage = 0; load(0); }}>
+              on:change={() => load()}>
               <option value="">All Scores</option>
               <option value="low">Low (&lt;50)</option>
               <option value="medium">Below Good (&lt;80)</option>
@@ -203,7 +241,7 @@
           <div class="filter-section">
             <label class="filter-section-label">OS Status</label>
             <select class="filter-select" bind:value={filterEol}
-              on:change={() => { currentPage = 0; load(0); }}>
+              on:change={() => load()}>
               <option value="">All</option>
               <option value="EOL">EOL</option>
               <option value="SUPPORTED">Supported</option>
@@ -224,14 +262,14 @@
             <span class="filter-tag" style="border-color: #d97706">
               <span class="filter-tag-dot" style="background-color: #d97706"></span>
               Score: {filterScore === 'low' ? 'Low (<50)' : 'Below Good (<80)'}
-              <button class="filter-tag-remove" on:click={() => { filterScore = ''; currentPage = 0; load(0); }}>&times;</button>
+              <button class="filter-tag-remove" on:click={() => { filterScore = ''; load(); }}>&times;</button>
             </span>
           {/if}
           {#if filterEol}
             <span class="filter-tag" style="border-color: {filterEol === 'EOL' ? '#dc2626' : filterEol === 'SUPPORTED' ? '#16a34a' : '#6b7280'}">
               <span class="filter-tag-dot" style="background-color: {filterEol === 'EOL' ? '#dc2626' : filterEol === 'SUPPORTED' ? '#16a34a' : '#6b7280'}"></span>
               OS: {eolLabel(filterEol)}
-              <button class="filter-tag-remove" on:click={() => { filterEol = ''; currentPage = 0; load(0); }}>&times;</button>
+              <button class="filter-tag-remove" on:click={() => { filterEol = ''; load(); }}>&times;</button>
             </span>
           {/if}
         </div>
@@ -245,12 +283,6 @@
           </div>
 
           <div class="table-card">
-            <Pagination
-              page={currentPage} {totalPages} {totalElements} size={pageSize}
-              on:pageChange={e => { currentPage = e.detail.page; load(currentPage); }}
-              on:pageSizeChange={e => { pageSize = e.detail.size; currentPage = 0; load(0); }}
-            />
-
             <div class="table-container">
               {#if loading}
                 <div class="table-msg">Loading…</div>
@@ -274,8 +306,26 @@
                       <th></th>
                     </tr>
                   </thead>
+                  {#each grouped as group (group.key)}
                     <tbody>
-                    {#each postures as device (device.deviceId)}
+                      <!-- svelte-ignore a11y-click-events-have-key-events a11y-no-noninteractive-element-interactions -->
+                      <tr class="inst-header" on:click={() => toggleInstitution(group.key)}>
+                        <td colspan="10">
+                          <div class="inst-header-inner">
+                            <span class="inst-chevron">{expandedInstitutions.has(group.key) ? '▼' : '▶'}</span>
+                            <span class="inst-key">{group.key}</span>
+                            <span class="inst-count">{group.devices.length} device{group.devices.length !== 1 ? 's' : ''}</span>
+                            {#if group.avgScore != null}
+                              <span class="inst-avg score-text-{scoreColor(group.avgScore)}">avg {group.avgScore}</span>
+                            {/if}
+                            {#if group.hasIssues}
+                              <span class="inst-warn">⚠ below 80</span>
+                            {/if}
+                          </div>
+                        </td>
+                      </tr>
+                      {#if expandedInstitutions.has(group.key)}
+                        {#each group.devices as device (device.deviceId)}
                           <tr on:click={() => openPanel(device)}>
                             <td class="mono-cell">{device.deviceAgentId ?? device.deviceId}</td>
                             <td class="os-cell">{device.osVersion ?? '—'}</td>
@@ -313,7 +363,9 @@
                             </td>
                           </tr>
                         {/each}
+                      {/if}
                     </tbody>
+                  {/each}
                 </table>
               {/if}
             </div>
@@ -644,6 +696,26 @@
   }
   .check-divider { height: 1px; background: #f3f4f6; margin: 4px 0; }
 
+  /* Institution accordion header rows */
+  tr.inst-header { cursor: pointer; }
+  tr.inst-header td { padding: 0; border-bottom: 1px solid #e5e7eb; }
+  tr.inst-header:hover td { background: #f1f5f9; }
+  .inst-header-inner {
+    display: flex; align-items: center; gap: 0.75rem;
+    padding: 0.55rem 0.75rem;
+    background: #f1f5f9;
+    font-size: 0.78rem;
+  }
+  .inst-chevron { color: #6b7280; font-size: 0.65rem; flex-shrink: 0; width: 10px; }
+  .inst-key { font-weight: 700; color: #1e3a5f; font-size: 0.82rem; letter-spacing: 0.2px; }
+  .inst-count { color: #6b7280; font-size: 0.75rem; }
+  .inst-avg { font-weight: 700; font-size: 0.75rem; }
+  .inst-warn {
+    font-size: 0.72rem; font-weight: 600; color: #b45309;
+    background: #fef3c7; border: 1px solid #fde68a;
+    border-radius: 10px; padding: 1px 8px;
+  }
+
   /* Dark mode */
   :global(.dark-mode) .content-frame { border-color: #374151; background: #1f2937; }
   :global(.dark-mode) .filter-sidebar            { background: #1f2937; border-right-color: #374151; }
@@ -684,6 +756,13 @@
   :global(.dark-mode) .img-badge.drift { background: #450a0a; color: #fca5a5; }
   :global(.dark-mode) .img-badge.unknown { background: #1e293b; color: #94a3b8; }
 
+  :global(.dark-mode) .inst-header-inner { background: #1a2744; }
+  :global(.dark-mode) tr.inst-header:hover td { background: #243356; }
+  :global(.dark-mode) tr.inst-header td { border-bottom-color: #374151; }
+  :global(.dark-mode) .inst-key   { color: #93c5fd; }
+  :global(.dark-mode) .inst-count { color: #6b7280; }
+  :global(.dark-mode) .inst-warn  { background: #451a03; border-color: #78350f; color: #fbbf24; }
+
   :global(.dark-mode) .panel        { background: #1e293b; }
   :global(.dark-mode) .panel-footer { background: #162032; border-top-color: #334155; }
   :global(.dark-mode) .panel-score-row { background: #111827; }