feat(switcher): searchable/filterable org switcher (#16)

At MSP scale (100+ orgs) the org/workspace switcher dropdown was an
un-scrollable wall. Add a type-to-filter search box.

- Sticky search input at the top of the switcher menu, shown once the list
  reaches a threshold (>= 8 workspaces); below that the plain list is fine.
- Live client-side filter: case-insensitive substring match on
  "organization name + workspace name" (data-search haystack per row). The
  full list is already loaded from /me, so no extra requests.
- Keyboard nav: search is auto-focused on open; type filters, ArrowUp/Down
  move a highlight among visible rows, Enter selects (switches), Esc closes.
- "No matches" state when nothing matches; opening resets the filter.
- Refactored the switch action into a shared switchTo() used by both click
  and Enter.

Frontend only. Verified headless: filter narrows live, no-match state,
clear restores, arrow-key highlight. EN i18n added.

Closes #16.

frontend/css/main.css

@@ -76,6 +76,21 @@ body {
   max-height: 360px; padding: 4px 0; overflow-y: auto; z-index: 100;
 }
 .workspace-switcher.open .workspace-switcher-menu { display: block; }
+/* #16: sticky type-to-filter search header inside the (scrolling) menu. */
+.workspace-switcher-search {
+  position: sticky; top: 0; z-index: 1;
+  background: var(--bg-card); padding: 8px;
+  border-bottom: 1px solid var(--border);
+}
+.workspace-switcher-search input {
+  width: 100%; box-sizing: border-box; padding: 6px 8px;
+  background: var(--bg-input); border: 1px solid var(--border);
+  border-radius: var(--radius); color: var(--text-primary); font-size: 13px;
+}
+.workspace-switcher-search input:focus { outline: none; border-color: var(--accent); }
+.workspace-switcher-noresults {
+  padding: 12px; color: var(--text-muted); font-size: 13px; text-align: center;
+}
 .workspace-switcher-item {
   display: flex; align-items: center; gap: 8px;
   padding: 8px 12px; cursor: pointer;
@@ -84,6 +99,8 @@ body {
 }
 .workspace-switcher-item:last-child { border-bottom: none; }
 .workspace-switcher-item:hover { background: var(--bg-input); }
+/* keyboard-cursor highlight (arrow keys) - same surface as hover */
+.workspace-switcher-item.highlighted { background: var(--bg-input); }
 .workspace-switcher-item.current { font-weight: 600; }
 .workspace-switcher-item .check {
   flex-shrink: 0; color: var(--accent); width: 14px;

frontend/js/components/workspace-switcher.js

@@ -42,6 +42,12 @@ export function renderWorkspaceSwitcher(me) {
   const sorted = [...list].sort((a, b) => a.name.localeCompare(b.name));
   const current = sorted.find(w => w.id === currentId) || sorted[0];
 
+  // Issue #16: show a type-to-filter search box once the list is big enough to
+  // be painful to scroll (MSPs run 100+ orgs). Below the threshold a plain list
+  // is fine. The full list is already loaded from /me, so filtering is client-side.
+  const SHOW_SEARCH_THRESHOLD = 8;
+  const showSearch = sorted.length >= SHOW_SEARCH_THRESHOLD;
+
   container.innerHTML = `
     <button class="workspace-switcher-button" type="button" aria-haspopup="listbox" aria-expanded="false">
       <span class="ws-name" style="overflow:hidden;text-overflow:ellipsis;white-space:nowrap">${esc(current.name)}</span>
@@ -50,6 +56,11 @@ export function renderWorkspaceSwitcher(me) {
       </svg>
     </button>
     <div class="workspace-switcher-menu" role="listbox">
+      ${showSearch ? `
+      <div class="workspace-switcher-search">
+        <input type="text" class="ws-search-input" placeholder="${t('switcher.search_placeholder')}"
+               autocomplete="off" autocapitalize="off" spellcheck="false" aria-label="${t('switcher.search_placeholder')}">
+      </div>` : ''}
       ${sorted.map(w => {
         const countStr = formatResourceCount(w.device_count, 'switcher.devices_count', 'switcher.no_devices');
         const orgName = w.organization_name || '';
@@ -57,8 +68,10 @@ export function renderWorkspaceSwitcher(me) {
                        : orgName            ? esc(orgName)
                        : countStr           ? esc(countStr)
                                             : '';
+        // Searchable haystack: org name + workspace name, lowercased.
+        const haystack = `${orgName} ${w.name}`.toLowerCase();
         return `
-        <div class="workspace-switcher-item ${w.id === currentId ? 'current' : ''}" data-workspace-id="${esc(w.id)}" role="option">
+        <div class="workspace-switcher-item ${w.id === currentId ? 'current' : ''}" data-workspace-id="${esc(w.id)}" data-search="${esc(haystack)}" role="option">
           <svg class="check" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="3" style="${w.id === currentId ? '' : 'visibility:hidden'}">
             <polyline points="20 6 9 17 4 12"/>
           </svg>
@@ -84,15 +97,86 @@ export function renderWorkspaceSwitcher(me) {
         </div>
       `;
       }).join('')}
+      <div class="workspace-switcher-noresults" style="display:none">${t('switcher.no_matches')}</div>
     </div>
   `;
 
   const button = container.querySelector('.workspace-switcher-button');
+  const searchInput = container.querySelector('.ws-search-input'); // null below threshold
+
+  // Shared switch action (used by click and keyboard Enter).
+  async function switchTo(wsId) {
+    if (wsId === currentId) { container.classList.remove('open'); return; }
+    try {
+      const resp = await api.switchWorkspace(wsId);
+      if (resp?.token) {
+        localStorage.setItem('token', resp.token);
+        window.location.reload();
+      } else {
+        showToast('Switch returned no token', 'error');
+      }
+    } catch (err) {
+      showToast(err.message || 'Failed to switch workspace', 'error');
+    }
+  }
+
+  // ---- type-to-filter + keyboard navigation (only when the search box renders) ----
+  const allItems = Array.from(container.querySelectorAll('.workspace-switcher-item'));
+  const noResults = container.querySelector('.workspace-switcher-noresults');
+  let highlightIdx = -1;
+  const visibleItems = () => allItems.filter(it => it.style.display !== 'none');
+
+  function setHighlight(idx) {
+    const vis = visibleItems();
+    allItems.forEach(it => it.classList.remove('highlighted'));
+    if (!vis.length) { highlightIdx = -1; return; }
+    highlightIdx = Math.max(0, Math.min(idx, vis.length - 1));
+    const el = vis[highlightIdx];
+    el.classList.add('highlighted');
+    el.scrollIntoView({ block: 'nearest' });
+  }
+
+  function applyFilter(q) {
+    const query = (q || '').trim().toLowerCase();
+    let anyVisible = false;
+    for (const it of allItems) {
+      const match = !query || it.dataset.search.includes(query);
+      it.style.display = match ? '' : 'none';
+      if (match) anyVisible = true;
+    }
+    if (noResults) noResults.style.display = anyVisible ? 'none' : '';
+    setHighlight(0);
+  }
+
+  if (searchInput) {
+    searchInput.addEventListener('input', () => applyFilter(searchInput.value));
+    searchInput.addEventListener('keydown', (e) => {
+      if (e.key === 'ArrowDown') { e.preventDefault(); setHighlight(highlightIdx + 1); }
+      else if (e.key === 'ArrowUp') { e.preventDefault(); setHighlight(highlightIdx - 1); }
+      else if (e.key === 'Enter') {
+        e.preventDefault();
+        const el = visibleItems()[highlightIdx];
+        if (el) switchTo(el.dataset.workspaceId);
+      } else if (e.key === 'Escape') {
+        e.preventDefault();
+        container.classList.remove('open');
+        button.setAttribute('aria-expanded', 'false');
+        button.focus();
+      }
+    });
+  }
+
   button.addEventListener('click', (e) => {
     e.stopPropagation();
     const opening = !container.classList.contains('open');
     container.classList.toggle('open');
     button.setAttribute('aria-expanded', String(opening));
+    // On open, reset the filter and focus the search box for immediate typing.
+    if (opening && searchInput) {
+      searchInput.value = '';
+      applyFilter('');
+      setTimeout(() => searchInput.focus(), 0);
+    }
   });
 
   // Pencil click opens the rename modal. Must stopPropagation so the click
@@ -121,22 +205,10 @@ export function renderWorkspaceSwitcher(me) {
   });
 
   container.querySelectorAll('.workspace-switcher-item').forEach(item => {
-    item.addEventListener('click', async (e) => {
+    item.addEventListener('click', (e) => {
       // Ignore clicks that originated on an icon button (each has its own handler).
       if (e.target.closest('.workspace-switcher-pencil, .workspace-switcher-members')) return;
-      const wsId = item.dataset.workspaceId;
-      if (wsId === currentId) { container.classList.remove('open'); return; }
-      try {
-        const resp = await api.switchWorkspace(wsId);
-        if (resp?.token) {
-          localStorage.setItem('token', resp.token);
-          window.location.reload();
-        } else {
-          showToast('Switch returned no token', 'error');
-        }
-      } catch (err) {
-        showToast(err.message || 'Failed to switch workspace', 'error');
-      }
+      switchTo(item.dataset.workspaceId);
     });
   });
 

frontend/js/i18n/en.js

@@ -1144,6 +1144,9 @@ export default {
   'switcher.devices_count_one': '1 device',
   'switcher.devices_count_other': '{n} devices',
   'switcher.no_devices': 'No devices',
+  // #16: searchable org/workspace switcher
+  'switcher.search_placeholder': 'Search organizations…',
+  'switcher.no_matches': 'No matches',
 
   // Workspace members (Slice 2A - read-only listing; 2B adds mutation keys).
   'members.title': 'Workspace members',