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/dialog/export/exportformatcombobox.cpp

@@ -36,31 +36,31 @@ ExportFormatComboBox::ExportFormatComboBox(Mode mode, QWidget *parent)
 
 	// Populate combobox formats
 	switch (mode) {
-	case kShowAllFormats:
-		custom_menu_->addAction(CreateHeader(icon::Video, tr("Video")));
-		PopulateType(Track::kVideo);
+	case k_show_all_formats:
+		custom_menu_->addAction(create_header(icon::video, tr("Video")));
+		populate_type(Track::k_video);
 		custom_menu_->addSeparator();
 
-		custom_menu_->addAction(CreateHeader(icon::Audio, tr("Audio")));
-		PopulateType(Track::kAudio);
+		custom_menu_->addAction(create_header(icon::audio, tr("Audio")));
+		populate_type(Track::k_audio);
 		custom_menu_->addSeparator();
 
-		custom_menu_->addAction(CreateHeader(icon::Subtitles, tr("Subtitle")));
-		PopulateType(Track::kSubtitle);
+		custom_menu_->addAction(create_header(icon::subtitles, tr("Subtitle")));
+		populate_type(Track::k_subtitle);
 		break;
-	case kShowAudioOnly:
-		PopulateType(Track::kAudio);
+	case k_show_audio_only:
+		populate_type(Track::k_audio);
 		break;
-	case kShowVideoOnly:
-		PopulateType(Track::kVideo);
+	case k_show_video_only:
+		populate_type(Track::k_video);
 		break;
-	case kShowSubtitlesOnly:
-		PopulateType(Track::kSubtitle);
+	case k_show_subtitles_only:
+		populate_type(Track::k_subtitle);
 		break;
 	}
 
 	connect(custom_menu_, &Menu::triggered, this,
-			&ExportFormatComboBox::HandleIndexChange);
+			&ExportFormatComboBox::handle_index_change);
 }
 
 void ExportFormatComboBox::showPopup()
@@ -69,43 +69,43 @@ void ExportFormatComboBox::showPopup()
 	custom_menu_->exec(mapToGlobal(QPoint(0, 0)));
 }
 
-void ExportFormatComboBox::SetFormat(ExportFormat::Format fmt)
+void ExportFormatComboBox::set_format(ExportFormat::Format fmt)
 {
 	current_ = fmt;
 	clear();
-	addItem(ExportFormat::GetName(current_));
+	addItem(ExportFormat::get_name(current_));
 }
 
-void ExportFormatComboBox::HandleIndexChange(QAction *a)
+void ExportFormatComboBox::handle_index_change(QAction *a)
 {
 	ExportFormat::Format f =
 		static_cast<ExportFormat::Format>(a->data().toInt());
-	SetFormat(f);
-	emit FormatChanged(f);
+	set_format(f);
+	emit format_changed(f);
 }
 
-void ExportFormatComboBox::PopulateType(Track::Type type)
+void ExportFormatComboBox::populate_type(Track::Type type)
 {
-	for (int i = 0; i < ExportFormat::kFormatCount; i++) {
+	for (int i = 0; i < ExportFormat::k_format_count; i++) {
 		ExportFormat::Format f = static_cast<ExportFormat::Format>(i);
 
-		if (type == Track::kVideo &&
-			!ExportFormat::GetVideoCodecs(f).isEmpty()) {
+		if (type == Track::k_video &&
+			!ExportFormat::get_video_codecs(f).isEmpty()) {
 			// Do nothing
-		} else if (type == Track::kAudio &&
-				   ExportFormat::GetVideoCodecs(f).isEmpty() &&
-				   !ExportFormat::GetAudioCodecs(f).isEmpty()) {
+		} else if (type == Track::k_audio &&
+				   ExportFormat::get_video_codecs(f).isEmpty() &&
+				   !ExportFormat::get_audio_codecs(f).isEmpty()) {
 			// Do nothing
-		} else if (type == Track::kSubtitle &&
-				   ExportFormat::GetVideoCodecs(f).isEmpty() &&
-				   ExportFormat::GetAudioCodecs(f).isEmpty() &&
-				   !ExportFormat::GetSubtitleCodecs(f).isEmpty()) {
+		} else if (type == Track::k_subtitle &&
+				   ExportFormat::get_video_codecs(f).isEmpty() &&
+				   ExportFormat::get_audio_codecs(f).isEmpty() &&
+				   !ExportFormat::get_subtitle_codecs(f).isEmpty()) {
 			// Do nothing
 		} else {
 			continue;
 		}
 
-		QString format_name = ExportFormat::GetName(f);
+		QString format_name = ExportFormat::get_name(f);
 
 		QAction *a = custom_menu_->addAction(format_name);
 		a->setData(i);
@@ -113,7 +113,7 @@ void ExportFormatComboBox::PopulateType(Track::Type type)
 	}
 }
 
-QWidgetAction *ExportFormatComboBox::CreateHeader(const QIcon &icon,
+QWidgetAction *ExportFormatComboBox::create_header(const QIcon &icon,
 												  const QString &title)
 {
 	QWidgetAction *a = new QWidgetAction(this);