Add PrintVault module: 3D print file manager integrated in HouseHub

- printvault.php: SPA with model grid, sidebar (categories + type filters), search
- modules/printvault/api.php: PHP proxy to PrintVault API (auth + CORS)
- modules/printvault/assets/printvault.js: model grid, upload modal, detail modal
- modules/printvault/assets/printvault.css: full light/dark theme
- Upload: drag&drop + form (name, category, tags)
- Detail modal: metadata, dimensions, GCode info, download, delete, "Voir en 3D" → PrintVault
- Integrated in header nav, home page, settings; translations fr/en/ca

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

settings.php

@@ -36,7 +36,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
     $action = $_POST['action'] ?? '';
 
     if ($action === 'set_modules' && $family_id) {
-        $all = ['calendar', 'budget', 'holidays', 'gifts', 'garage', 'memo', 'todo', 'groceries', 'calendar_ios'];
+        $all = ['calendar', 'budget', 'holidays', 'gifts', 'garage', 'memo', 'todo', 'groceries', 'calendar_ios', 'printvault'];
         $enabled = array_values(array_filter($all, fn($m) => isset($_POST['mod_' . $m])));
         if (empty($enabled)) {
             $error = "Vous devez garder au moins un module actif.";
@@ -309,6 +309,7 @@ require __DIR__ . '/header.php';
           'todo'     => ['icon' => '✅', 'label' => tr('menu_todo')],
           'groceries' => ['icon' => '🛒', 'label' => tr('menu_groceries')],
           'calendar_ios' => ['icon' => '📱', 'label' => tr('menu_calendar_ios')],
+          'printvault'  => ['icon' => '🖨️', 'label' => tr('menu_printvault')],
       ];
     ?>
     <form method="post">