fix(measure): task_execute full-screen layout + hide UI for tasks without measurements

Pagina /measure/execute/<task_id>:
- Il pannello destro (info subtask + tolerance + numpad) e la sidebar
  marker spariscono quando il task non ha subtask: l'utente vede solo
  intestazione + disegno a tutta larghezza, senza colonne vuote né
  tastierina numerica fuori contesto.
- Risolta la scrollbar verticale: la pagina ora occupa esattamente
  l'altezza del viewport. Il layout sfrutta nuovi block override in
  base.html (body_class, wrapper_class, main_class, footer) per
  disattivare scroll e footer solo su questa pagina, lasciando intatte
  le altre.

Cataloghi i18n: aggiunte traduzioni EN/IT mancanti e rimossi i flag
"fuzzy" auto-generati da pybabel update (Flask-Babel ignora i fuzzy,
mostrando il msgid italiano anche in EN).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/frontend/flask_app/templates/measure/task_execute.html

@@ -1,6 +1,12 @@
 {% extends "base.html" %}
 {% block title %}{{ task.title or 'Task' }} — {{ _('Misure') }} — TieMeasureFlow{% endblock %}
 
+{# Full-screen layout: no body scroll, no footer, main fills available space #}
+{% block body_class %}h-screen overflow-hidden{% endblock %}
+{% block wrapper_class %}h-full{% endblock %}
+{% block main_class %}flex-1 min-h-0{% endblock %}
+{% block footer %}{% endblock %}
+
 {% block extra_head %}
 <style>
   /* Annotation viewer container */
@@ -57,7 +63,7 @@
   window.__allTaskIds = {{ all_task_ids|tojson }};
 </script>
 
-<div class="h-screen flex flex-col overflow-hidden"
+<div class="h-full flex flex-col overflow-hidden"
      x-data="taskExecute()"
      x-init="init()"
      @numpad-confirm.window="handleMeasurement($event.detail.value, $event.detail.inputMethod)"
@@ -124,9 +130,10 @@
   <div class="flex-1 flex overflow-hidden">
 
     {# ──────────────────────────────────────────────
-       LEFT SIDEBAR — Marker list (vertical)
+       LEFT SIDEBAR — Marker list (vertical, hidden when no subtasks)
        ────────────────────────────────────────────── #}
-    <div class="shrink-0 w-14 md:w-16 bg-[var(--bg-card)] border-r border-[var(--border-color)] flex flex-col sidebar-markers overflow-y-auto">
+    <div x-show="subtasks.length > 0"
+         class="shrink-0 w-14 md:w-16 bg-[var(--bg-card)] border-r border-[var(--border-color)] flex flex-col sidebar-markers overflow-y-auto">
       <template x-for="(st, idx) in subtasks" :key="st.id">
         <button @click="goToSubtask(idx)"
                 class="relative flex flex-col items-center justify-center py-2.5 px-1 border-b border-[var(--border-color)] transition-all duration-200"
@@ -213,9 +220,10 @@
     </div>
 
     {# ──────────────────────────────────────────────
-       RIGHT PANEL — Info + tolerances + numpad
+       RIGHT PANEL — Info + tolerances + numpad (hidden when no subtasks)
        ────────────────────────────────────────────── #}
-    <div class="shrink-0 w-72 lg:w-80 bg-[var(--bg-card)] border-l border-[var(--border-color)] flex flex-col right-panel overflow-y-auto">
+    <div x-show="subtasks.length > 0"
+         class="shrink-0 w-72 lg:w-80 bg-[var(--bg-card)] border-l border-[var(--border-color)] flex flex-col right-panel overflow-y-auto">
 
       {# ---- Subtask header ---- #}
       <div class="p-3 border-b border-[var(--border-color)]" x-show="currentSubtask">
@@ -310,7 +318,7 @@
       </div>
 
       {# ---- Measurement feedback ---- #}
-      <div class="px-3 pt-2" x-data="{ get nominal() { return currentSubtask?.nominal || 0; },
+      <div class="px-3 pt-2" x-show="currentSubtask" x-data="{ get nominal() { return currentSubtask?.nominal || 0; },
                                         get utl() { return currentSubtask?.utl || 0; },
                                         get uwl() { return currentSubtask?.uwl || 0; },
                                         get lwl() { return currentSubtask?.lwl || 0; },
@@ -319,8 +327,8 @@
         {% include "components/measurement_feedback.html" %}
       </div>
 
-      {# ---- Numpad ---- #}
-      <div class="px-3 py-2 relative flex-1">
+      {# ---- Numpad (only when a subtask is active) ---- #}
+      <div class="px-3 py-2 relative flex-1" x-show="currentSubtask">
         {# Saving overlay #}
         <div x-show="saving"
              x-transition
@@ -338,10 +346,11 @@
       </div>
 
       {# ---- Next measurement indicator ---- #}
-      <div class="px-3 pb-2">
+      <div class="px-3 pb-2" x-show="currentSubtask">
         {% include "components/next_measurement.html" %}
       </div>
 
+
       {# ---- Error message ---- #}
       <div x-show="errorMessage"
            x-transition