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>

includes/lang/ca.php

@@ -148,6 +148,10 @@ return [
     'cta_check'          => 'Marcar',
     'cta_cart'           => 'Anar a comprar',
     'cta_sync'           => 'Sincronitzar',
+    'mod_printvault_name' => 'PrintVault',
+    'mod_printvault_desc' => 'Gestioneu els vostres fitxers d\'impressió 3D — STL, 3MF, GCode.',
+    'menu_printvault'    => 'PrintVault',
+    'cta_print'          => 'Imprimir',
 
     // ==========================================
     // FAMILY CALENDAR

includes/lang/en.php

@@ -149,6 +149,10 @@ return [
     'cta_check'          => 'Check off',
     'cta_cart'           => 'Go shopping',
     'cta_sync'           => 'Sync',
+    'mod_printvault_name' => 'PrintVault',
+    'mod_printvault_desc' => 'Manage your 3D print files — STL, 3MF, GCode with interactive viewer.',
+    'menu_printvault'    => 'PrintVault',
+    'cta_print'          => 'Print',
 
     // ==========================================
     // FAMILY CALENDAR

includes/lang/fr.php

@@ -151,6 +151,10 @@ return [
     'cta_check'          => 'Cocher',
     'cta_cart'           => 'Faire les courses',
     'cta_sync'           => 'Synchroniser',
+    'mod_printvault_name' => 'PrintVault',
+    'mod_printvault_desc' => 'Gérez vos fichiers d\'impression 3D — STL, 3MF, GCode avec viewer interactif.',
+    'menu_printvault'    => 'PrintVault',
+    'cta_print'          => 'Imprimer',
 
     // ==========================================
     // FAMILY CALENDAR