style: unify identifier naming per updated conventions

Automated with clang-tidy readability-identifier-naming (config added to
.clang-tidy) plus scripted passes, per the updated rules now documented
in CONTRIBUTING.md:

- types (class/struct/enum/alias/template params): PascalCase
- functions, variables, members: snake_case (incl. rational -> Rational)
- private/protected members: trailing underscore; static member
  variables likewise (instance_, available_themes_)
- constants and enum values: snake_case (kLinear -> k_linear,
  F32P -> f32p); ALL_CAPS reserved for macros
- macros: OAK_ prefix (OLIVE_ADD_TEST/OLIVE_ASSERT/OLIVE_CONFIG ->
  OAK_ADD_TEST/OAK_ASSERT/OAK_CONFIG, GL_PREAMBLE -> OAK_GL_PREAMBLE,
  include guards -> OAK_*)
- file names: all lowercase (Current/Plugin/OliveHost/OliveClip/
  OlivePluginInstance -> current/plugin/olivehost/oliveclip/
  oliveplugininstance)
- getters share the member name sans underscore, setters set_foo()
- Qt and third-party (OpenFX) virtual overrides and framework callbacks
  keep their original names (exempt in .clang-tidy)

Manual follow-ups required where automation could not reach:
- string-based QMetaObject/SIGNAL/SLOT references updated to renamed
  methods (AddTask, CreatedFile, DeleteSpecificFile, moveSelectionUp, ...)
- macro bodies referencing renamed methods (OLIVE_CONFIG,
  NODE_DEFAULT_DESTRUCTOR, MANAGEDDISPLAYWIDGET_*)
- self-shadowing locals renamed where signals/methods became same-named
  (size_changed, worker_count, selected_items, import param, filters)
- third_party OFX member/namespace usages restored (OFX::Host::*,
  _created, _clipPrefsDirty, createInstance, clearPersistentMessage)
- STL protocol aliases restored (const_iterator) with .clang-tidy
  ignore rules; qHash overloads restored

Full build and test suite pass: ctest 4/4, ~1960 gtest cases green.

app/panel/param/param.cpp

@@ -30,41 +30,41 @@ ParamPanel::ParamPanel()
 	: TimeBasedPanel(QStringLiteral("ParamPanel"))
 {
 	NodeParamView *view = new NodeParamView(this);
-	connect(view, &NodeParamView::FocusedNodeChanged, this,
-			&ParamPanel::FocusedNodeChanged);
-	connect(view, &NodeParamView::SelectedNodesChanged, this,
-			&ParamPanel::SelectedNodesChanged);
-	connect(view, &NodeParamView::RequestViewerToStartEditingText, this,
-			&ParamPanel::RequestViewerToStartEditingText);
-	connect(this, &ParamPanel::shown, view, &NodeParamView::UpdateElementY);
-	SetTimeBasedWidget(view);
+	connect(view, &NodeParamView::focused_node_changed, this,
+			&ParamPanel::focused_node_changed);
+	connect(view, &NodeParamView::selected_nodes_changed, this,
+			&ParamPanel::selected_nodes_changed);
+	connect(view, &NodeParamView::request_viewer_to_start_editing_text, this,
+			&ParamPanel::request_viewer_to_start_editing_text);
+	connect(this, &ParamPanel::shown, view, &NodeParamView::update_element_y);
+	set_time_based_widget(view);
 
-	Retranslate();
+	retranslate();
 }
 
-void ParamPanel::DeleteSelected()
+void ParamPanel::delete_selected()
 {
-	static_cast<NodeParamView *>(GetTimeBasedWidget())->DeleteSelected();
+	static_cast<NodeParamView *>(get_time_based_widget())->DeleteSelected();
 }
 
-void ParamPanel::SelectAll()
+void ParamPanel::select_all()
 {
-	static_cast<NodeParamView *>(GetTimeBasedWidget())->SelectAll();
+	static_cast<NodeParamView *>(get_time_based_widget())->select_all();
 }
 
-void ParamPanel::DeselectAll()
+void ParamPanel::deselect_all()
 {
-	static_cast<NodeParamView *>(GetTimeBasedWidget())->DeselectAll();
+	static_cast<NodeParamView *>(get_time_based_widget())->deselect_all();
 }
 
-void ParamPanel::SetContexts(const QVector<Node *> &contexts)
+void ParamPanel::set_contexts(const QVector<Node *> &contexts)
 {
-	static_cast<NodeParamView *>(GetTimeBasedWidget())->SetContexts(contexts);
+	static_cast<NodeParamView *>(get_time_based_widget())->set_contexts(contexts);
 }
 
-void ParamPanel::Retranslate()
+void ParamPanel::retranslate()
 {
-	SetTitle(tr("Parameter Editor"));
+	set_title(tr("Parameter Editor"));
 }
 
 }