feat(access): only return granted users; add search endpoint

Listing every user in the system on the access page didn't scale —
schools have thousands of user rows. Now:
  - index() only returns users that already have a UnifiPageGrant
    somewhere. Groups stay fully listed (few of them).
  - new searchUsers(q) endpoint returns up to 20 typeahead matches
    against name or email (min 2 chars).

v1.5.2.

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

src/Http/Controllers/UnifiPagesAccessController.php

@@ -34,6 +34,12 @@ class UnifiPagesAccessController extends Controller
             ->get()
             ->groupBy('nav_item_id');
 
+        // Only return users that ALREADY have grants. The full users list
+        // can be enormous (thousands of rows); the operator adds more via
+        // the searchUsers endpoint as needed.
+        $grantedUserIds = $grants->flatten(1)->where('grantee_type', 'user')->pluck('grantee_id')->unique();
+        $users = User::whereIn('id', $grantedUserIds)->orderBy('name')->get(['id', 'name', 'email']);
+
         return response()->json([
             'pages' => $pages->map(fn ($p) => [
                 'id'         => $p->id,
@@ -42,11 +48,34 @@ class UnifiPagesAccessController extends Controller
                 'user_ids'   => $grants->get($p->id, collect())->where('grantee_type', 'user')->pluck('grantee_id')->all(),
                 'group_ids'  => $grants->get($p->id, collect())->where('grantee_type', 'group')->pluck('grantee_id')->all(),
             ])->values(),
-            'users'  => User::orderBy('name')->get(['id', 'name', 'email']),
+            'users'  => $users,
             'groups' => Group::orderBy('name')->get(['id', 'name', 'is_super']),
         ]);
     }
 
+    /**
+     * Typeahead-style search for users to add to the access matrix.
+     * Returns up to 20 matches against name or email. Empty query returns
+     * an empty array — caller must enter at least 2 chars.
+     */
+    public function searchUsers(Request $request)
+    {
+        $q = trim((string) $request->query('q', ''));
+        if (strlen($q) < 2) {
+            return response()->json(['users' => []]);
+        }
+
+        $users = User::where(function ($w) use ($q) {
+            $w->where('name',  'like', '%' . $q . '%')
+              ->orWhere('email', 'like', '%' . $q . '%');
+        })
+            ->orderBy('name')
+            ->limit(20)
+            ->get(['id', 'name', 'email']);
+
+        return response()->json(['users' => $users]);
+    }
+
     public function update(Request $request, NavItem $navItem)
     {
         $app = DashboardApp::where('slug', 'unifi')->first();