feat(12-02): wire all template strings to Alpine i18n store

- dashboard.html: headings, quick actions, empty states wired to x-text
- printers.html: h1, add button, h2 wired to x-text
- printers_new.html: all form labels (span pattern), options, submit buttons wired
- clients.html: headings, label, submit button wired
- client_detail.html: back link, section heading wired
- drivers.html: all headings, label, buttons, spinner wired
- packages.html: heading, description, table headers, empty state wired
- printer_detail.html: all dt/dd, section headings, copy buttons, script/export links wired with conditional Jinja2 for color/collate/client
- partials/printer_list.html: table headers, Yes/No cells (Alpine ternary), delete button wired
- partials/printer_edit_modal.html: edit trigger, modal title, all labels (span pattern), options, save/cancel wired
- partials/client_list.html: empty state, table headers wired
- partials/driver_list.html: table headers, unknown values, empty state wired
- Fix test_printers_library_no_form: check form element attribute instead of UI label string (now in i18n dict)

imptune/templates/partials/driver_list.html

@@ -17,10 +17,10 @@
   <table>
     <thead>
       <tr>
-        <th>Filename</th>
-        <th>Driver Name(s)</th>
-        <th>Architecture</th>
-        <th>Uploaded</th>
+        <th x-data x-text="$store.i18n.t('driver_filename')">Filename</th>
+        <th x-data x-text="$store.i18n.t('driver_names_col')">Driver Name(s)</th>
+        <th x-data x-text="$store.i18n.t('architecture')">Architecture</th>
+        <th x-data x-text="$store.i18n.t('uploaded_at')">Uploaded</th>
       </tr>
     </thead>
     <tbody>
@@ -35,16 +35,16 @@
             {% endfor %}
           </select>
           {% else %}
-          <em>Unknown</em>
+          <em x-data x-text="$store.i18n.t('unknown')">Unknown</em>
           {% endif %}
         </td>
-        <td>{{ item.driver.architecture or "Unknown" }}</td>
+        <td>{% if item.driver.architecture %}{{ item.driver.architecture }}{% else %}<span x-data x-text="$store.i18n.t('unknown')">Unknown</span>{% endif %}</td>
         <td>{{ item.driver.uploaded_at }}</td>
       </tr>
       {% endfor %}
     </tbody>
   </table>
   {% else %}
-  <p>No drivers uploaded yet.</p>
+  <p x-data x-text="$store.i18n.t('no_drivers')">No drivers uploaded yet.</p>
   {% endif %}
 </div>