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/dashboard.html

@@ -1,19 +1,19 @@
 {% extends "base.html" %}
 
 {% block content %}
-<h1>Dashboard</h1>
+<h1 x-data x-text="$store.i18n.t('dashboard')">Dashboard</h1>
 
 <div class="quick-actions">
-  <a href="/printers" class="btn-action">New Printer</a>
-  <a href="/drivers" class="btn-action">Upload Driver</a>
-  <a href="/packages" class="btn-action">Export Package</a>
+  <a href="/printers" class="btn-action" x-data x-text="$store.i18n.t('new_printer')">New Printer</a>
+  <a href="/drivers" class="btn-action" x-data x-text="$store.i18n.t('upload_driver_btn')">Upload Driver</a>
+  <a href="/packages" class="btn-action" x-data x-text="$store.i18n.t('export_package')">Export Package</a>
 </div>
 
 <section class="recent-activity">
-  <h2>Recent Activity</h2>
+  <h2 x-data x-text="$store.i18n.t('recent_activity')">Recent Activity</h2>
 
   <div class="activity-section">
-    <h3>Recent Printers</h3>
+    <h3 x-data x-text="$store.i18n.t('recent_printers')">Recent Printers</h3>
     {% if recent_printers %}
       <ul>
         {% for printer in recent_printers %}
@@ -21,12 +21,12 @@
         {% endfor %}
       </ul>
     {% else %}
-      <p class="empty-state">No printers configured yet.</p>
+      <p class="empty-state" x-data x-text="$store.i18n.t('no_printers')">No printers configured yet.</p>
     {% endif %}
   </div>
 
   <div class="activity-section">
-    <h3>Recent Packages</h3>
+    <h3 x-data x-text="$store.i18n.t('recent_packages')">Recent Packages</h3>
     {% if recent_packages %}
       <ul>
         {% for package in recent_packages %}
@@ -34,7 +34,7 @@
         {% endfor %}
       </ul>
     {% else %}
-      <p class="empty-state">No packages exported yet.</p>
+      <p class="empty-state" x-data x-text="$store.i18n.t('no_packages')">No packages exported yet.</p>
     {% endif %}
   </div>
 </section>