fix: version badge rendering, Jinja2 scoping, navbar i18n, missing GET task endpoint

- Fix version badge showing [object Object] or Python dict dump in
  select_recipe, task_list, and task_complete templates by accessing
  current_version.version_number instead of the whole object
- Fix recipe_editor.html Internal Server Error caused by Jinja2 block
  scoping: {% set %} variables from block content were invisible in
  block extra_js, replaced with direct recipe.* references
- Fix task_editor.html SyntaxError from Italian apostrophe in
  nell'eliminazione breaking JS string literals, switched to |tojson
- Add i18n {{ _() }} wrappers to all hardcoded navbar strings (desktop
  and mobile menus) so language toggle works correctly
- Add app title text "TieMeasureFlow" next to logo in navbar
- Add missing GET /api/tasks/{task_id} endpoint on server that caused
  405 Method Not Allowed when starting measurements

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

client/templates/measure/select_recipe.html

@@ -150,7 +150,7 @@
             </span>
             <span class="badge badge-neutral text-xs"
                   x-show="recipe.current_version || recipe.version"
-                  x-text="'v' + (recipe.current_version || recipe.version || '')">
+                  x-text="'v' + (recipe.current_version ? recipe.current_version.version_number : (recipe.version || ''))">
             </span>
           </div>