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/drivers.html

@@ -1,9 +1,9 @@
 {% extends "base.html" %}
 {% block content %}
-<h1>Drivers</h1>
+<h1 x-data x-text="$store.i18n.t('drivers_title')">Drivers</h1>
 
 <section>
-  <h2>Upload Driver Package</h2>
+  <h2 x-data x-text="$store.i18n.t('upload_driver_section')">Upload Driver Package</h2>
   <form
     hx-post="/drivers/upload"
     hx-encoding="multipart/form-data"
@@ -11,15 +11,15 @@
     hx-swap="outerHTML"
     hx-indicator="#upload-spinner"
   >
-    <label for="driver-file">Driver Package (ZIP containing .inf + driver files)</label>
+    <label for="driver-file" x-data x-text="$store.i18n.t('driver_package_label')">Driver Package (ZIP containing .inf + driver files)</label>
     <input type="file" id="driver-file" name="file" accept=".zip" required>
-    <button type="submit">Upload</button>
-    <span id="upload-spinner" class="htmx-indicator" aria-busy="true">Uploading...</span>
+    <button type="submit" x-data x-text="$store.i18n.t('upload_btn')">Upload</button>
+    <span id="upload-spinner" class="htmx-indicator" aria-busy="true" x-data x-text="$store.i18n.t('uploading')">Uploading...</span>
   </form>
 </section>
 
 <section>
-  <h2>Driver Library</h2>
+  <h2 x-data x-text="$store.i18n.t('driver_library')">Driver Library</h2>
   {% include "partials/driver_list.html" %}
 </section>
 {% endblock %}