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/maker/recipe_editor.html

@@ -585,8 +585,8 @@
 function recipeEditor() {
   return {
     // ---- Mode ----
-    isNew: {{ 'true' if is_new else 'false' }},
-    recipeId: {{ recipe_id|tojson if recipe_id else 'null' }},
+    isNew: {{ 'true' if recipe is none else 'false' }},
+    recipeId: {{ recipe.id|tojson if recipe else 'null' }},
 
     // ---- Form data ----
     code: {{ (recipe.code if recipe else '')|tojson }},
@@ -595,12 +595,12 @@ function recipeEditor() {
     changeNotes: '',
 
     // ---- File upload ----
-    currentFilePath: {{ (current_version.tasks[0].file_path if current_version and current_version.tasks and current_version.tasks|length > 0 else None)|tojson }},
+    currentFilePath: {{ (recipe.current_version.tasks[0].file_path if recipe and recipe.current_version and recipe.current_version.tasks and recipe.current_version.tasks|length > 0 else None)|tojson }},
     uploadingFile: false,
     dragOver: false,
 
     // ---- Annotation state (managed by annotation-editor.js) ----
-    annotationsJson: {{ (current_version.tasks[0].annotations_json if current_version and current_version.tasks and current_version.tasks|length > 0 and current_version.tasks[0].annotations_json else None)|tojson }},
+    annotationsJson: {{ (recipe.current_version.tasks[0].annotations_json if recipe and recipe.current_version and recipe.current_version.tasks and recipe.current_version.tasks|length > 0 and recipe.current_version.tasks[0].annotations_json else None)|tojson }},
     annoTool: 'select',
     annoSelected: false,
 
@@ -610,8 +610,8 @@ function recipeEditor() {
     errorMessage: '',
 
     // ---- Versioning ----
-    versions: {{ versions|tojson }},
-    currentVersion: {{ (current_version.version_number if current_version else 0)|tojson }},
+    versions: {{ (recipe.versions if recipe and recipe.versions else [])|tojson }},
+    currentVersion: {{ (recipe.current_version.version_number if recipe and recipe.current_version else 0)|tojson }},
 
     // ============================================================
     // Init

client/templates/maker/task_editor.html

@@ -1227,7 +1227,7 @@ function taskEditor() {
           this.successMessage = '{{ _("Task eliminato") }}';
         } else {
           const data = await resp.json();
-          this.errorMessage = data.detail || '{{ _("Errore nell\'eliminazione del task") }}';
+          this.errorMessage = data.detail || {{ _("Errore nell'eliminazione del task")|tojson }};
         }
       } catch (err) {
         console.error('deleteTask error:', err);
@@ -1510,7 +1510,7 @@ function taskEditor() {
           this.successMessage = '{{ _("Misurazione eliminata") }}';
         } else {
           const data = await resp.json();
-          this.errorMessage = data.detail || '{{ _("Errore nell\'eliminazione della misurazione") }}';
+          this.errorMessage = data.detail || {{ _("Errore nell'eliminazione della misurazione")|tojson }};
         }
       } catch (err) {
         console.error('deleteSubtask error:', err);