Refactor and document: fix cert filenames, add Doxygen, improve demo

Refactoring (issues 1,3,4,5,7,8,9,10 from review):
- Replace hardcoded cert filenames with certFile/keyFile properties
- Add 30s timeout to certificate trust QEventLoop
- Cache servers() QVariantList instead of rebuilding per call
- Validate URLs before passing to QtOpcUa
- Use ComboBox valueRole for robust enum mapping
- Add certificate trust dialog to demo
- Remove unnecessary RowLayout wrapper
- Remove debug output from BuildDeps.cmake

Documentation:
- Add Doxygen file blocks to all C++ files
- Document AuthMode enum, toAuthenticationInformation(), key
  Q_INVOKABLE methods, certificateTrustRequested signal contract
- Convert section banners to standard format
- Add file/target comments to CMake and QML files

1 files changed, 69 insertions, 20 deletions

diff --git a/src/BobinkClient.cpp b/src/BobinkClient.cpp
index ea61583..a067489 100644
--- a/src/BobinkClient.cpp
+++ b/src/BobinkClient.cpp
@@ -1,3 +1,7 @@
+/**
+ * @file   BobinkClient.cpp
+ * @brief  BobinkClient implementation.
+ */
 #include "BobinkClient.h"
 #include "BobinkAuth.h"
 
@@ -12,6 +16,7 @@ static QString defaultPkiDir()
            + QStringLiteral("/pki");
 }
 
+/** @brief Create the standard OPC UA PKI directory tree. */
 static void ensurePkiDirs(const QString &base)
 {
     for (const auto *sub : {"own/certs", "own/private",
@@ -69,7 +74,9 @@ void BobinkClient::setupClient()
             this, &BobinkClient::handleFindServersFinished);
 }
 
-// --- Connection properties ---
+/* ======================================
+ *  Connection properties
+ * ====================================== */
 
 bool BobinkClient::connected() const { return m_connected; }
 
@@ -95,7 +102,9 @@ void BobinkClient::setAuth(BobinkAuth *auth)
 
 QOpcUaClient *BobinkClient::opcuaClient() const { return m_client; }
 
-// --- Connection methods ---
+/* ======================================
+ *  Connection methods
+ * ====================================== */
 
 void BobinkClient::connectToServer()
 {
@@ -112,7 +121,12 @@ void BobinkClient::connectToServer()
         return;
     }
 
-    m_client->requestEndpoints(QUrl(m_serverUrl));
+    QUrl url(m_serverUrl);
+    if (!url.isValid()) {
+        emit connectionError(QStringLiteral("Invalid server URL: %1").arg(m_serverUrl));
+        return;
+    }
+    m_client->requestEndpoints(url);
 }
 
 void BobinkClient::disconnectFromServer()
@@ -135,7 +149,9 @@ void BobinkClient::rejectCertificate()
         m_certLoop->quit();
 }
 
-// --- Discovery properties ---
+/* ======================================
+ *  Discovery properties
+ * ====================================== */
 
 QString BobinkClient::discoveryUrl() const { return m_discoveryUrl; }
 
@@ -169,18 +185,12 @@ const QList<QOpcUaApplicationDescription> &BobinkClient::discoveredServers() con
 
 QVariantList BobinkClient::servers() const
 {
-    QVariantList list;
-    for (const auto &s : m_discoveredServers) {
-        QVariantMap entry;
-        entry[QStringLiteral("serverName")] = s.applicationName().text();
-        entry[QStringLiteral("applicationUri")] = s.applicationUri();
-        entry[QStringLiteral("discoveryUrls")] = QVariant::fromValue(s.discoveryUrls());
-        list.append(entry);
-    }
-    return list;
+    return m_serversCache;
 }
 
-// --- PKI ---
+/* ======================================
+ *  PKI
+ * ====================================== */
 
 QString BobinkClient::pkiDir() const { return m_pkiDir; }
 
@@ -193,14 +203,36 @@ void BobinkClient::setPkiDir(const QString &path)
     emit pkiDirChanged();
 }
 
+QString BobinkClient::certFile() const { return m_certFile; }
+
+void BobinkClient::setCertFile(const QString &path)
+{
+    if (m_certFile == path)
+        return;
+    m_certFile = path;
+    emit certFileChanged();
+}
+
+QString BobinkClient::keyFile() const { return m_keyFile; }
+
+void BobinkClient::setKeyFile(const QString &path)
+{
+    if (m_keyFile == path)
+        return;
+    m_keyFile = path;
+    emit keyFileChanged();
+}
+
 void BobinkClient::applyPki()
 {
     if (!m_client || m_pkiDir.isEmpty())
         return;
 
     QOpcUaPkiConfiguration pki;
-    pki.setClientCertificateFile(m_pkiDir + QStringLiteral("/own/certs/BobinkDemo_cert.der"));
-    pki.setPrivateKeyFile(m_pkiDir + QStringLiteral("/own/private/BobinkDemo_key.pem"));
+    if (!m_certFile.isEmpty())
+        pki.setClientCertificateFile(m_certFile);
+    if (!m_keyFile.isEmpty())
+        pki.setPrivateKeyFile(m_keyFile);
     pki.setTrustListDirectory(m_pkiDir + QStringLiteral("/trusted/certs"));
     pki.setRevocationListDirectory(m_pkiDir + QStringLiteral("/trusted/crl"));
     pki.setIssuerListDirectory(m_pkiDir + QStringLiteral("/issuers/certs"));
@@ -212,7 +244,9 @@ void BobinkClient::applyPki()
         m_client->setApplicationIdentity(pki.applicationIdentity());
 }
 
-// --- Discovery methods ---
+/* ======================================
+ *  Discovery methods
+ * ====================================== */
 
 void BobinkClient::startDiscovery()
 {
@@ -240,11 +274,17 @@ void BobinkClient::stopDiscovery()
 
 void BobinkClient::doDiscovery()
 {
-    if (m_client && !m_discoveryUrl.isEmpty())
-        m_client->findServers(QUrl(m_discoveryUrl));
+    if (!m_client || m_discoveryUrl.isEmpty())
+        return;
+    QUrl url(m_discoveryUrl);
+    if (!url.isValid())
+        return;
+    m_client->findServers(url);
 }
 
-// --- Private slots ---
+/* ======================================
+ *  Private slots
+ * ====================================== */
 
 void BobinkClient::handleStateChanged(QOpcUaClient::ClientState state)
 {
@@ -291,6 +331,7 @@ void BobinkClient::handleConnectError(QOpcUaErrorState *errorState)
 
         QEventLoop loop;
         m_certLoop = &loop;
+        QTimer::singleShot(30000, &loop, &QEventLoop::quit);
         loop.exec();
         m_certLoop = nullptr;
 
@@ -311,5 +352,13 @@ void BobinkClient::handleFindServersFinished(
         return;
 
     m_discoveredServers = servers;
+    m_serversCache.clear();
+    for (const auto &s : m_discoveredServers) {
+        QVariantMap entry;
+        entry[QStringLiteral("serverName")] = s.applicationName().text();
+        entry[QStringLiteral("applicationUri")] = s.applicationUri();
+        entry[QStringLiteral("discoveryUrls")] = QVariant::fromValue(s.discoveryUrls());
+        m_serversCache.append(entry);
+    }
     emit serversChanged();
 }