Initial implementation of qobuz-qt

- Rust backend (qobuz-backend static lib): Qobuz API client (reqwest/tokio),
  Symphonia audio decoder, CPAL audio output, extern "C" FFI bridge
- Qt 6 frontend mirroring spotify-qt layout: toolbar with playback controls,
  left library dock, central track list, right search panel
- Auth: email/password login with MD5-signed requests; session token persisted
  via QSettings
- Playback: double-click a track → Rust fetches stream URL → Symphonia decodes
  → CPAL outputs to default audio device
- Dark Fusion palette matching spotify-qt feel

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/view/sidepanel/view.cpp

@@ -0,0 +1,139 @@
+#include "view.hpp"
+
+#include <QVBoxLayout>
+#include <QHBoxLayout>
+#include <QPushButton>
+#include <QJsonArray>
+
+static constexpr int IdRole   = Qt::UserRole + 1;
+static constexpr int TypeRole = Qt::UserRole + 2;
+
+namespace SidePanel
+{
+
+// ---- SearchTab ----
+
+SearchTab::SearchTab(QobuzBackend *backend, QWidget *parent)
+    : QWidget(parent)
+    , m_backend(backend)
+{
+    auto *layout = new QVBoxLayout(this);
+    layout->setContentsMargins(4, 4, 4, 4);
+
+    // Search bar
+    auto *barLayout = new QHBoxLayout;
+    m_searchBox     = new QLineEdit(this);
+    m_searchBox->setPlaceholderText(tr("Search Qobuz…"));
+    m_searchBox->setClearButtonEnabled(true);
+    auto *searchBtn = new QPushButton(tr("Go"), this);
+    barLayout->addWidget(m_searchBox);
+    barLayout->addWidget(searchBtn);
+    layout->addLayout(barLayout);
+
+    // Result tabs
+    m_resultTabs = new QTabWidget(this);
+
+    m_trackResults  = new QTreeWidget(this);
+    m_trackResults->setHeaderLabels({tr("Title"), tr("Artist"), tr("Album")});
+    m_trackResults->setRootIsDecorated(false);
+
+    m_albumResults  = new QTreeWidget(this);
+    m_albumResults->setHeaderLabels({tr("Album"), tr("Artist")});
+    m_albumResults->setRootIsDecorated(false);
+
+    m_artistResults = new QTreeWidget(this);
+    m_artistResults->setHeaderLabels({tr("Artist")});
+    m_artistResults->setRootIsDecorated(false);
+
+    m_resultTabs->addTab(m_trackResults,  tr("Tracks"));
+    m_resultTabs->addTab(m_albumResults,  tr("Albums"));
+    m_resultTabs->addTab(m_artistResults, tr("Artists"));
+    layout->addWidget(m_resultTabs);
+
+    connect(searchBtn,   &QPushButton::clicked,  this, &SearchTab::onSearchSubmit);
+    connect(m_searchBox, &QLineEdit::returnPressed, this, &SearchTab::onSearchSubmit);
+
+    connect(m_backend, &QobuzBackend::searchResult, this, &SearchTab::onSearchResult);
+
+    connect(m_trackResults,  &QTreeWidget::itemDoubleClicked, this, &SearchTab::onItemDoubleClicked);
+    connect(m_albumResults,  &QTreeWidget::itemDoubleClicked, this, &SearchTab::onItemDoubleClicked);
+    connect(m_artistResults, &QTreeWidget::itemDoubleClicked, this, &SearchTab::onItemDoubleClicked);
+}
+
+void SearchTab::onSearchSubmit()
+{
+    const QString q = m_searchBox->text().trimmed();
+    if (!q.isEmpty())
+        m_backend->search(q, 0, 20);
+}
+
+void SearchTab::onSearchResult(const QJsonObject &result)
+{
+    // Populate tracks
+    m_trackResults->clear();
+    const QJsonArray tracks = result["tracks"].toObject()["items"].toArray();
+    for (const auto &v : tracks) {
+        const QJsonObject t = v.toObject();
+        const QString performer = t["performer"].toObject()["name"].toString();
+        const QString album     = t["album"].toObject()["title"].toString();
+        auto *item = new QTreeWidgetItem(m_trackResults,
+            QStringList{t["title"].toString(), performer, album});
+        item->setData(0, IdRole,   static_cast<qint64>(t["id"].toDouble()));
+        item->setData(0, TypeRole, QStringLiteral("track"));
+    }
+
+    // Populate albums
+    m_albumResults->clear();
+    const QJsonArray albums = result["albums"].toObject()["items"].toArray();
+    for (const auto &v : albums) {
+        const QJsonObject a = v.toObject();
+        const QString artist = a["artist"].toObject()["name"].toString();
+        auto *item = new QTreeWidgetItem(m_albumResults,
+            QStringList{a["title"].toString(), artist});
+        item->setData(0, IdRole,   a["id"].toString());
+        item->setData(0, TypeRole, QStringLiteral("album"));
+    }
+
+    // Populate artists
+    m_artistResults->clear();
+    const QJsonArray artists = result["artists"].toObject()["items"].toArray();
+    for (const auto &v : artists) {
+        const QJsonObject ar = v.toObject();
+        auto *item = new QTreeWidgetItem(m_artistResults,
+            QStringList{ar["name"].toString()});
+        item->setData(0, IdRole,   static_cast<qint64>(ar["id"].toDouble()));
+        item->setData(0, TypeRole, QStringLiteral("artist"));
+    }
+}
+
+void SearchTab::onItemDoubleClicked(QTreeWidgetItem *item, int)
+{
+    if (!item) return;
+    const QString type = item->data(0, TypeRole).toString();
+
+    if (type == QStringLiteral("track")) {
+        emit trackPlayRequested(item->data(0, IdRole).toLongLong());
+    } else if (type == QStringLiteral("album")) {
+        emit albumSelected(item->data(0, IdRole).toString());
+    } else if (type == QStringLiteral("artist")) {
+        emit artistSelected(item->data(0, IdRole).toLongLong());
+    }
+}
+
+// ---- View ----
+
+View::View(QobuzBackend *backend, QWidget *parent)
+    : QDockWidget(tr("Search"), parent)
+{
+    setObjectName(QStringLiteral("searchPanel"));
+    setFeatures(QDockWidget::DockWidgetMovable | QDockWidget::DockWidgetClosable);
+
+    m_search = new SearchTab(backend, this);
+    setWidget(m_search);
+
+    connect(m_search, &SearchTab::albumSelected,       this, &View::albumSelected);
+    connect(m_search, &SearchTab::artistSelected,      this, &View::artistSelected);
+    connect(m_search, &SearchTab::trackPlayRequested,  this, &View::trackPlayRequested);
+}
+
+} // namespace SidePanel