fix(task_execute): letture doppie, sessione scaduta, ciclo rifiutato dal server (#13, #12, #29, #37)

#13 — handleMeasurement era rientrante: saving tornava false prima della
pausa di 1s di feedback, currentIndex avanzava dopo. Una seconda lettura in
quella finestra salvava due volte la stessa quota e saltava la successiva.
Guardia unica this.busy: true all'ingresso, false su ogni uscita della
funzione; l'ingresso è bloccato anche con showCompletionOverlay,
showSupervisorModal, isPaused o cycleConfirmed pendenti. Una lettura scartata
non sparisce in silenzio: errorMessage "Lettura ignorata: attendere".

#12 — dopo la scadenza del token CSRF (config lato server, lotto B2) il POST
tornava 400 in HTML: response.json() lanciava, finiva nel catch generico e
l'operatore vedeva "Errore di rete" invece che "Sessione scaduta". Aggiunto
try/catch dedicato sul parsing e controllo di result.csrf_expired /
session_expired, sia in handleMeasurement che in postProduction(); la lettura
non salvata resta sul display.

#29 — confirmCycle mostrava il ciclo chiuso anche quando il server rifiutava
/cycle (produzione aperta, postProduction torna null): cadeva nel ramo "nessuna
produzione", incrementando cycleCount in locale. Ora, con produzione aperta, un
rifiuto del server ripristina cycleConfirmed=false, riapre l'overlay di
completamento e mostra l'errore (già in productionError); il ramo locale resta
riservato a quando non c'è produzione aperta.

#37 punto 9 — il blocco capoturno era deciso su passFailStatus (preview
client, prima del salvataggio) invece che su result.pass_fail del server;
ora la risposta del server decide sia il blocco che i conteggi locali.

Completa anche il lato pagina di #27: aggiunto il listener per l'evento
numpad-error (dispatchato da numpad.js) cosi' la lettura rifiutata dal calibro
è visibile all'operatore, non solo intercettata in silenzio.

Stringhe nuove in messages.po (it/en): "Sessione scaduta: ricaricare la
pagina", "Lettura ignorata: attendere", "Lettura del calibro rifiutata: valore
troppo grande".

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

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

@@ -68,6 +68,7 @@
      x-init="init()"
      @numpad-confirm.window="handleMeasurement($event.detail.value, $event.detail.inputMethod)"
      @numpad-rejected.window="onNumpadRejected($event.detail)"
+     @numpad-error.window="onNumpadError($event.detail)"
      @marker-click.window="goToSubtaskByMarker($event.detail.marker_number)">
 
   {# ================================================================
@@ -932,6 +933,11 @@ function taskExecute() {
     currentIndex: 0,
     measurements: [],   // [{subtask_id, value, pass_fail, deviation}, ...]
     saving: false,
+    // The single reentrancy guard for handleMeasurement (#13): true for the
+    // whole time a reading is being processed, including the 1s feedback
+    // pause after the save where "saving" alone used to go false too early.
+    // "saving" stays as it was - it only drives the UI spinner.
+    busy: false,
     errorMessage: '',
     showCompletionOverlay: false,
 
@@ -942,6 +948,7 @@ function taskExecute() {
     timerActive: false,
     timerRemaining: 0,
     _timerInterval: null,
+    _timerDeadline: null,  // wall-clock ms the countdown is aimed at (#37.7)
     cycleCount: 0,
     productionStarted: false,
 
@@ -1094,6 +1101,13 @@ function taskExecute() {
       // Rejoin whatever production is already open at this station.
       await this.loadProductionRun();
       await this.loadPendingAuthorisation();
+      // A tablet left to sleep drifts (#37.7): catch the countdown back up to
+      // the server's own clock, the same source adoptProductionRun already
+      // trusts on load, as soon as the tab is visible again.
+      var self = this;
+      document.addEventListener('visibilitychange', function () {
+        if (document.visibilityState === 'visible') self.loadProductionRun();
+      });
     },
 
     /* Is a quote already waiting for the capoturno?
@@ -1187,10 +1201,30 @@ function taskExecute() {
       }
     },
 
+    /* The numpad refused the reading itself (e.g. a caliper burst whose
+       integer part does not fit) rather than a rule about who may type it.
+       Same error line, so there is still one place to look. */
+    onNumpadError(detail) {
+      this.errorMessage = '{{ _("Lettura del calibro rifiutata: valore troppo grande") }}';
+    },
+
     // ---- Handle numpad confirm ----
     async handleMeasurement(value, inputMethod) {
-      if (!this.currentSubtask || this.saving) return;
+      if (!this.currentSubtask) return;
 
+      // Single reentrancy guard (#13): a second reading arriving while the
+      // first one is still being saved - or while the operator is stuck
+      // behind the modal/overlay the first one opened - must not become its
+      // own measurement (double record, one quote skipped). It is not
+      // silently dropped either: the same error line other rejections use
+      // says so.
+      if (this.busy || this.showCompletionOverlay || this.showSupervisorModal ||
+          this.isPaused || this.cycleConfirmed) {
+        this.errorMessage = '{{ _("Lettura ignorata: attendere") }}';
+        return;
+      }
+
+      this.busy = true;
       this.currentValue = value;
       this.errorMessage = '';
 
@@ -1225,17 +1259,43 @@ function taskExecute() {
           }),
         });
 
-        const result = await response.json();
+        let result;
+        try {
+          result = await response.json();
+        } catch (parseErr) {
+          // The server answered but not with JSON: a CSRF-expired POST gets
+          // the login page's HTML back, not a payload. Distinguish that from
+          // a dead network so the operator is told to reload rather than to
+          // retry blindly; the unsaved reading stays on screen either way.
+          this.errorMessage = '{{ _("Sessione scaduta: ricaricare la pagina") }}';
+          this.saving = false;
+          this.busy = false;
+          return;
+        }
+
+        if (result && (result.csrf_expired || result.session_expired)) {
+          this.errorMessage = '{{ _("Sessione scaduta: ricaricare la pagina") }}';
+          this.saving = false;
+          this.busy = false;
+          return;
+        }
 
         if (!response.ok || result.error) {
           this.errorMessage = result.detail || '{{ _("Errore nel salvataggio della misurazione") }}';
           this.saving = false;
+          this.busy = false;
           return;
         }
 
+        // The server decides pass/fail from the recipe's official tolerances;
+        // passFailStatus is only a live preview while the value is on screen,
+        // not what a capoturno block or the pass/warning/fail counts should
+        // be keyed on.
+        const serverPassFail = result.pass_fail || pf;
+
         // Record measurement locally
         const existingIdx = this.measurements.findIndex(m => m.subtask_id === this.currentSubtask.id);
-        const mEntry = { subtask_id: this.currentSubtask.id, value, pass_fail: pf, deviation: dev };
+        const mEntry = { subtask_id: this.currentSubtask.id, value, pass_fail: serverPassFail, deviation: dev };
         if (existingIdx !== -1) {
           this.measurements.splice(existingIdx, 1, mEntry);
         } else {
@@ -1249,9 +1309,10 @@ function taskExecute() {
 
         // Out of tolerance: nothing moves until the capoturno says so, or until
         // this same quote is measured again and comes out inside tolerance.
-        if (pf === 'fail') {
+        if (serverPassFail === 'fail') {
           this.pendingFail = { id: result.id, subtask_id: this.currentSubtask.id };
           this.openSupervisorModal('out_of_tolerance');
+          this.busy = false;
           return;
         }
 
@@ -1270,18 +1331,22 @@ function taskExecute() {
           // Produzione") or once production is running ("Conferma ciclo").
           if (!this.productionStarted && !this.isLastTask) {
             this.goToNextTask();
+            this.busy = false;
             return;
           }
           this.showCompletionOverlay = true;
+          this.busy = false;
           return;
         }
 
         this.advanceToNext();
+        this.busy = false;
 
       } catch (err) {
         console.error('Save measurement error:', err);
         this.errorMessage = '{{ _("Errore di rete. Riprovare.") }}';
         this.saving = false;
+        this.busy = false;
       }
     },
 
@@ -1374,6 +1439,13 @@ function taskExecute() {
           }
           return;
         }
+
+        // The server refused to close the cycle (line stopped, production
+        // closed, network down): the screen must not show a cycle that never
+        // actually closed. productionError already carries why.
+        this.cycleConfirmed = false;
+        this.showCompletionOverlay = true;
+        return;
       }
 
       // No production open (recipe run outside a production): keep the old local
@@ -1414,6 +1486,13 @@ function taskExecute() {
           body: JSON.stringify(body || {}),
         });
         const data = await resp.json().catch(() => null);
+        // Not JSON at all (CSRF-expired POSTs get the login page's HTML
+        // back), or the server flagged the session as gone: same "reload"
+        // message handleMeasurement gives for the same failure (#12).
+        if (!data || data.csrf_expired || data.session_expired) {
+          this.productionError = '{{ _("Sessione scaduta: ricaricare la pagina") }}';
+          return null;
+        }
         if (!resp.ok) {
           this.productionError = (data && data.detail) || '{{ _("Errore di comunicazione con il server") }}';
           return null;
@@ -1434,6 +1513,12 @@ function taskExecute() {
       this.stopMeasurementTimer();
       this.timerRemaining = seconds;
       this.timerActive = true;
+      // The wall clock, not a tick count (#37.7): a tablet asleep for a few
+      // minutes has to catch the countdown up in one jump when it wakes, not
+      // replay the ticks it missed while suspended - setInterval does not
+      // fire while a tab is backgrounded, so a tick-based countdown drifted
+      // behind by exactly however long the tab was hidden.
+      this._timerDeadline = Date.now() + seconds * 1000;
       // Landing on a page that is already late is the same event as going late
       // while sitting on it; being back in time re-arms the announcement.
       if (seconds <= 0) {
@@ -1448,7 +1533,7 @@ function taskExecute() {
 
     onSecond() {
       const wasAnnounced = this.dueAnnounced;
-      this.timerRemaining--;
+      this.timerRemaining = Math.ceil((this._timerDeadline - Date.now()) / 1000);
       if (this.timerRemaining <= 0) this.onMeasurementDue();
 
       if (wasAnnounced && this.redirectIn > 0) {

src/frontend/flask_app/translations/en/LC_MESSAGES/messages.po

@@ -2748,3 +2748,15 @@ msgstr "Error generating report"
 #~ msgid "Errore nel caricamento dei task: %(detail)s"
 #~ msgstr "Error loading tasks: %(detail)s"
 
+#: templates/measure/task_execute.html:1268
+msgid "Sessione scaduta: ricaricare la pagina"
+msgstr "Session expired: reload the page"
+
+#: templates/measure/task_execute.html:1219
+msgid "Lettura ignorata: attendere"
+msgstr "Reading ignored: please wait"
+
+#: templates/measure/task_execute.html:1194
+msgid "Lettura del calibro rifiutata: valore troppo grande"
+msgstr "Caliper reading refused: value too large"
+

src/frontend/flask_app/translations/it/LC_MESSAGES/messages.po

@@ -2736,3 +2736,15 @@ msgstr "Errore nella generazione del report"
 #~ msgid "Errore nel caricamento dei task: %(detail)s"
 #~ msgstr "Errore nel caricamento dei task: %(detail)s"
 
+#: templates/measure/task_execute.html:1268
+msgid "Sessione scaduta: ricaricare la pagina"
+msgstr "Sessione scaduta: ricaricare la pagina"
+
+#: templates/measure/task_execute.html:1219
+msgid "Lettura ignorata: attendere"
+msgstr "Lettura ignorata: attendere"
+
+#: templates/measure/task_execute.html:1194
+msgid "Lettura del calibro rifiutata: valore troppo grande"
+msgstr "Lettura del calibro rifiutata: valore troppo grande"
+