fix(sessions): lista vuota sul device — modello C++ con ruoli (v0.1.2)

Causa: su Qt 5.6 (kit Sailfish 5.1) una QVariantList di QVariantMap
usata come model non fa risolvere i campi nei delegate QML
(model.title/message_count/updated_at = undefined -> righe vuote), pur
con payload corretto dal server (verificato con cattura reale del 12/09).

- Nuovo src/sessionsmodel.{h,cpp}: QAbstractListModel con ruoli
  session_id/title/message_count/updated_at; api.sessions ora e' il
  modello, api.sessionsCount per lo stato "nessuna sessione"
- /api/sessions con sidebar_source=webui&exclude_hidden=1 (come la
  sidebar del browser: solo sessioni WebUI, niente CLI/cron/nascoste)
- SessionsPage: describe(message_count, updated_at) con parametri espliciti
- PROTOCOL.md: payload sessions verificato + nota del pitfall Qt 5.6

src/apiclient.cpp

@@ -15,6 +15,7 @@ ApiClient::ApiClient(Settings *settings, QObject *parent)
     : QObject(parent)
     , m_settings(settings)
     , m_jar(new CookieJar(this))
+    , m_sessionsModel(new SessionsModel(this))
     , m_loggedIn(false)
     , m_busy(false)
     , m_streaming(false)
@@ -170,7 +171,7 @@ void ApiClient::logout()
     });
     m_jar->clear();
     setLoggedIn(false);
-    m_sessions.clear();
+    m_sessionsModel->setSessions(QVariantList());
     emit sessionsChanged();
     m_session.clear();
     emit sessionChanged();
@@ -181,7 +182,14 @@ void ApiClient::logout()
 void ApiClient::refreshSessions()
 {
     setBusy(true);
-    QNetworkReply *reply = m_nam.get(jsonRequest(QStringLiteral("/api/sessions")));
+    // Stessi parametri della sidebar del WebUI: solo sessioni WebUI visibili
+    // (senza parametri arriverebbero anche le CLI/cron e le nascoste).
+    QUrl url = apiUrl(QStringLiteral("/api/sessions"));
+    QUrlQuery q;
+    q.addQueryItem(QStringLiteral("sidebar_source"), QStringLiteral("webui"));
+    q.addQueryItem(QStringLiteral("exclude_hidden"), QStringLiteral("1"));
+    url.setQuery(q);
+    QNetworkReply *reply = m_nam.get(QNetworkRequest(url));
     connect(reply, &QNetworkReply::finished, this, [this, reply]() {
         reply->deleteLater();
         setBusy(false);
@@ -192,11 +200,16 @@ void ApiClient::refreshSessions()
         }
         const QJsonObject obj = QJsonDocument::fromJson(body).object();
         const QJsonArray arr = obj.value(QStringLiteral("sessions")).toArray();
-        m_sessions = arr.toVariantList();
+        m_sessionsModel->setSessions(arr.toVariantList());
         emit sessionsChanged();
     });
 }
 
+int ApiClient::sessionsCount() const
+{
+    return m_sessionsModel->rowCount();
+}
+
 void ApiClient::openSession(const QString &id)
 {
     setLastError(QString());

src/apiclient.h

@@ -9,6 +9,7 @@
 
 #include "cookiejar.h"
 #include "settings.h"
+#include "sessionsmodel.h"
 #include "sseparser.h"
 
 class QHttpMultiPart;
@@ -36,7 +37,8 @@ class ApiClient : public QObject
     Q_PROPERTY(bool streaming READ streaming NOTIFY streamingChanged)
     Q_PROPERTY(bool transcribing READ transcribing NOTIFY transcribingChanged)
     Q_PROPERTY(QString lastError READ lastError NOTIFY lastErrorChanged)
-    Q_PROPERTY(QVariantList sessions READ sessions NOTIFY sessionsChanged)
+    Q_PROPERTY(SessionsModel *sessions READ sessions NOTIFY sessionsChanged)
+    Q_PROPERTY(int sessionsCount READ sessionsCount NOTIFY sessionsChanged)
     Q_PROPERTY(QVariantMap session READ session NOTIFY sessionChanged)
 
 public:
@@ -47,7 +49,8 @@ public:
     bool streaming() const { return m_streaming; }
     bool transcribing() const { return m_transcribing; }
     QString lastError() const { return m_lastError; }
-    QVariantList sessions() const { return m_sessions; }
+    SessionsModel *sessions() const { return m_sessionsModel; }
+    int sessionsCount() const;
     QVariantMap session() const { return m_session; }
 
     // Avvio: verifica lo stato auth (cookie persistito o auth disabilitata).
@@ -119,7 +122,7 @@ private:
     bool m_transcribing;
     QString m_lastError;
 
-    QVariantList m_sessions;
+    SessionsModel *m_sessionsModel;
     QVariantMap m_session;
 
     QString m_streamId;

src/sessionsmodel.cpp

@@ -0,0 +1,52 @@
+#include "sessionsmodel.h"
+
+#include <QVariantMap>
+
+SessionsModel::SessionsModel(QObject *parent)
+    : QAbstractListModel(parent)
+{
+}
+
+int SessionsModel::rowCount(const QModelIndex &parent) const
+{
+    if (parent.isValid())
+        return 0;
+    return m_rows.size();
+}
+
+QVariant SessionsModel::data(const QModelIndex &index, int role) const
+{
+    if (!index.isValid() || index.row() < 0 || index.row() >= m_rows.size())
+        return QVariant();
+
+    const QVariantMap row = m_rows.at(index.row()).toMap();
+    switch (role) {
+    case SessionIdRole:
+        return row.value(QStringLiteral("session_id"));
+    case TitleRole:
+        return row.value(QStringLiteral("title"));
+    case MessageCountRole:
+        return row.value(QStringLiteral("message_count"));
+    case UpdatedAtRole:
+        return row.value(QStringLiteral("updated_at"));
+    default:
+        return QVariant();
+    }
+}
+
+QHash<int, QByteArray> SessionsModel::roleNames() const
+{
+    QHash<int, QByteArray> names;
+    names[SessionIdRole] = "session_id";
+    names[TitleRole] = "title";
+    names[MessageCountRole] = "message_count";
+    names[UpdatedAtRole] = "updated_at";
+    return names;
+}
+
+void SessionsModel::setSessions(const QVariantList &sessions)
+{
+    beginResetModel();
+    m_rows = sessions;
+    endResetModel();
+}

src/sessionsmodel.h

@@ -0,0 +1,38 @@
+#ifndef SESSIONSMODEL_H
+#define SESSIONSMODEL_H
+
+#include <QAbstractListModel>
+#include <QVariantList>
+
+// Modello delle sessioni per la lista QML.
+//
+// Perché non una QVariantList di mappe: sul kit Sailfish 5.1 (Qt 5.6) i campi
+// di una QVariantMap dentro una lista non si risolvono nei delegate
+// (model.campo = undefined -> righe vuote, pur con dati corretti dal server).
+// I ruoli di un QAbstractListModel sono il meccanismo supportato da sempre
+// (stesso principio dei ListModel usati con successo negli altri progetti).
+class SessionsModel : public QAbstractListModel
+{
+    Q_OBJECT
+public:
+    enum Roles {
+        SessionIdRole = Qt::UserRole + 1,
+        TitleRole,
+        MessageCountRole,
+        UpdatedAtRole,
+    };
+
+    explicit SessionsModel(QObject *parent = nullptr);
+
+    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
+    QVariant data(const QModelIndex &index, int role) const override;
+    QHash<int, QByteArray> roleNames() const override;
+
+    // Sostituisce i dati (reset del modello: la lista QML si aggiorna).
+    void setSessions(const QVariantList &sessions);
+
+private:
+    QVariantList m_rows;
+};
+
+#endif // SESSIONSMODEL_H