Add desktop app service and VM dev session tooling

Introduces a new `core/applications` QML/C++ module (`Nebula.Applications`) to discover `.desktop` entries, expose filterable application models, and launch installed apps safely from the shell. The desktop launcher now uses real installed apps with themed icon loading and fallback glyphs, adds output-aware surface sizing via `OutputTracker`, and wires in image/icon providers. It also adds VMware-focused Sway/shell wrapper scripts, updates Sway config/session env defaults, and refreshes README docs to document the new development flow and Desktop 0.1 behavior.

core/applications/ApplicationModel.cpp

@@ -0,0 +1,93 @@
+#include "ApplicationModel.hpp"
+
+#include <algorithm>
+#include <utility>
+
+ApplicationModel::ApplicationModel(QObject *parent)
+    : QAbstractListModel(parent)
+{
+}
+
+int ApplicationModel::rowCount(const QModelIndex &parent) const
+{
+    if (parent.isValid())
+        return 0;
+    return m_entries.size();
+}
+
+int ApplicationModel::count() const
+{
+    return m_entries.size();
+}
+
+QVariant ApplicationModel::data(const QModelIndex &index, int role) const
+{
+    if (!index.isValid() || index.row() < 0 || index.row() >= m_entries.size())
+        return {};
+
+    const DesktopEntry &entry = m_entries.at(index.row());
+    switch (role) {
+    case DesktopIdRole:
+    case Qt::UserRole:
+        return entry.desktopId;
+    case NameRole:
+    case Qt::DisplayRole:
+        return entry.name;
+    case GenericNameRole:
+        return entry.genericName;
+    case CommentRole:
+        return entry.comment;
+    case IconNameRole:
+        return entry.icon;
+    case CategoriesRole:
+        return entry.categories;
+    case TerminalRole:
+        return entry.terminal;
+    default:
+        return {};
+    }
+}
+
+QHash<int, QByteArray> ApplicationModel::roleNames() const
+{
+    return {
+        {DesktopIdRole, QByteArrayLiteral("desktopId")},
+        {NameRole, QByteArrayLiteral("name")},
+        {GenericNameRole, QByteArrayLiteral("genericName")},
+        {CommentRole, QByteArrayLiteral("comment")},
+        {IconNameRole, QByteArrayLiteral("iconName")},
+        {CategoriesRole, QByteArrayLiteral("categories")},
+        {TerminalRole, QByteArrayLiteral("terminal")},
+    };
+}
+
+void ApplicationModel::setEntries(QVector<DesktopEntry> entries)
+{
+    std::sort(entries.begin(), entries.end(), [](const DesktopEntry &left, const DesktopEntry &right) {
+        const int order = QString::localeAwareCompare(left.name, right.name);
+        if (order != 0)
+            return order < 0;
+        return left.desktopId < right.desktopId;
+    });
+
+    beginResetModel();
+    m_entries = std::move(entries);
+    endResetModel();
+    emit countChanged();
+}
+
+const DesktopEntry *ApplicationModel::entryAt(int row) const
+{
+    if (row < 0 || row >= m_entries.size())
+        return nullptr;
+    return &m_entries.at(row);
+}
+
+const DesktopEntry *ApplicationModel::entryById(const QString &desktopId) const
+{
+    for (const DesktopEntry &entry : m_entries) {
+        if (entry.desktopId == desktopId)
+            return &entry;
+    }
+    return nullptr;
+}