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/curve/curve.cpp

@@ -28,49 +28,49 @@ CurvePanel::CurvePanel()
 	: TimeBasedPanel(QStringLiteral("CurvePanel"))
 {
 	// Create main widget and set it
-	SetTimeBasedWidget(new CurveWidget(this));
+	set_time_based_widget(new CurveWidget(this));
 
 	// Set strings
-	Retranslate();
+	retranslate();
 }
 
-void CurvePanel::DeleteSelected()
+void CurvePanel::delete_selected()
 {
-	static_cast<CurveWidget *>(GetTimeBasedWidget())->DeleteSelected();
+	static_cast<CurveWidget *>(get_time_based_widget())->DeleteSelected();
 }
 
-void CurvePanel::SelectAll()
+void CurvePanel::select_all()
 {
-	static_cast<CurveWidget *>(GetTimeBasedWidget())->SelectAll();
+	static_cast<CurveWidget *>(get_time_based_widget())->select_all();
 }
 
-void CurvePanel::DeselectAll()
+void CurvePanel::deselect_all()
 {
-	static_cast<CurveWidget *>(GetTimeBasedWidget())->DeselectAll();
+	static_cast<CurveWidget *>(get_time_based_widget())->deselect_all();
 }
 
-void CurvePanel::SetNodes(const QVector<Node *> &nodes)
+void CurvePanel::set_nodes(const QVector<Node *> &nodes)
 {
-	static_cast<CurveWidget *>(GetTimeBasedWidget())->SetNodes(nodes);
+	static_cast<CurveWidget *>(get_time_based_widget())->set_nodes(nodes);
 }
 
-void CurvePanel::IncreaseTrackHeight()
+void CurvePanel::increase_track_height()
 {
-	CurveWidget *c = static_cast<CurveWidget *>(GetTimeBasedWidget());
-	c->SetVerticalScale(c->GetVerticalScale() * 2);
+	CurveWidget *c = static_cast<CurveWidget *>(get_time_based_widget());
+	c->set_vertical_scale(c->get_vertical_scale() * 2);
 }
 
-void CurvePanel::DecreaseTrackHeight()
+void CurvePanel::decrease_track_height()
 {
-	CurveWidget *c = static_cast<CurveWidget *>(GetTimeBasedWidget());
-	c->SetVerticalScale(c->GetVerticalScale() * 0.5);
+	CurveWidget *c = static_cast<CurveWidget *>(get_time_based_widget());
+	c->set_vertical_scale(c->get_vertical_scale() * 0.5);
 }
 
-void CurvePanel::Retranslate()
+void CurvePanel::retranslate()
 {
-	TimeBasedPanel::Retranslate();
+	TimeBasedPanel::retranslate();
 
-	SetTitle(tr("Curve Editor"));
+	set_title(tr("Curve Editor"));
 }
 
 }