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, 17 insertions, 3 deletions

diff --git a/cmake/BuildDeps.cmake b/cmake/BuildDeps.cmake
index 8a1fa89..d105419 100644
--- a/cmake/BuildDeps.cmake
+++ b/cmake/BuildDeps.cmake
@@ -1,3 +1,13 @@
+# ======================================
+#  BuildDeps.cmake
+#
+#  Configure, build, and install open62541 and QtOpcUa from
+#  git submodules under deps/.
+#
+#  Skip detection: if the built .so already exists, the
+#  corresponding dep is skipped. Delete the file to rebuild.
+# ======================================
+
 set(OPEN62541_SOURCE_DIR "${CMAKE_SOURCE_DIR}/deps/open62541")
 set(OPEN62541_BUILD_DIR "${CMAKE_BINARY_DIR}/deps/open62541-build")
 set(OPEN62541_INSTALL_DIR "${CMAKE_BINARY_DIR}/deps/open62541-install")
@@ -18,7 +28,9 @@ if(NOT EXISTS "${QTOPCUA_SOURCE_DIR}/CMakeLists.txt")
   )
 endif()
 
-# --- open62541 ---
+# ======================================
+#  open62541
+# ======================================
 if(NOT EXISTS "${OPEN62541_INSTALL_DIR}/lib/libopen62541.so")
 
   message(STATUS "Configuring open62541 in ${OPEN62541_BUILD_DIR}...")
@@ -60,9 +72,10 @@ else()
   message(STATUS "open62541 already built, skipping")
 endif()
 
-# --- qtopcua ---
+# ======================================
+#  QtOpcUa
+# ======================================
 
-message(STATUS "CMAKE_PREFIX_PATH=${CMAKE_PREFIX_PATH}")
 find_program(QT_CMAKE_COMMAND bin/qt-cmake REQUIRED)
 
 if(NOT EXISTS "${QTOPCUA_BUILD_DIR}/lib/libQt6OpcUa.so")
@@ -76,6 +89,7 @@ if(NOT EXISTS "${QTOPCUA_BUILD_DIR}/lib/libQt6OpcUa.so")
       "${QTOPCUA_BUILD_DIR}"
       -G
       Ninja
+      # Use our locally-built open62541, not the bundled copy
       -DINPUT_open62541=system
       -DCMAKE_PREFIX_PATH=${OPEN62541_INSTALL_DIR})
   execute_process(COMMAND ${_cmd} RESULT_VARIABLE _result)