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.

tests/gtest/lut_file_field_test.cpp

@@ -15,21 +15,21 @@ namespace
 class LutLibraryConfigGuard {
 public:
 	LutLibraryConfigGuard()
-		: previous_(olive::Config::Current()[QStringLiteral("LUTLibraryPaths")]
+		: previous_(olive::Config::current()[QStringLiteral("LUTLibraryPaths")]
 						.toString())
 	{
 	}
 
 	~LutLibraryConfigGuard()
 	{
-		olive::Config::Current()[QStringLiteral("LUTLibraryPaths")] = previous_;
+		olive::Config::current()[QStringLiteral("LUTLibraryPaths")] = previous_;
 	}
 
 private:
 	QString previous_;
 };
 
-QString WriteFile(const QString &path)
+QString write_file(const QString &path)
 {
 	QFile file(path);
 	if (!file.open(QIODevice::WriteOnly)) {
@@ -49,16 +49,16 @@ TEST(LutFileField, PopulatesComboFromLibrary)
 	ASSERT_TRUE(dir.isValid());
 
 	const QString cube =
-		WriteFile(QDir(dir.path()).filePath(QStringLiteral("a.cube")));
+		write_file(QDir(dir.path()).filePath(QStringLiteral("a.cube")));
 	const QString three_dl =
-		WriteFile(QDir(dir.path()).filePath(QStringLiteral("b.3dl")));
+		write_file(QDir(dir.path()).filePath(QStringLiteral("b.3dl")));
 	const QString other =
-		WriteFile(QDir(dir.path()).filePath(QStringLiteral("c.txt")));
+		write_file(QDir(dir.path()).filePath(QStringLiteral("c.txt")));
 	ASSERT_FALSE(cube.isEmpty());
 	ASSERT_FALSE(three_dl.isEmpty());
 	ASSERT_FALSE(other.isEmpty());
 
-	olive::LUTLibrary::SetDirectories({ dir.path() });
+	olive::LUTLibrary::set_directories({ dir.path() });
 
 	olive::LutFileField field;
 
@@ -78,30 +78,30 @@ TEST(LutFileField, SelectionFollowsFilenameAndEmitsOnPick)
 	ASSERT_TRUE(dir.isValid());
 
 	const QString cube =
-		WriteFile(QDir(dir.path()).filePath(QStringLiteral("a.cube")));
+		write_file(QDir(dir.path()).filePath(QStringLiteral("a.cube")));
 	ASSERT_FALSE(cube.isEmpty());
 
-	olive::LUTLibrary::SetDirectories({ dir.path() });
+	olive::LUTLibrary::set_directories({ dir.path() });
 
 	olive::LutFileField field;
 
 	// A path that is not in the library shows the "Other" entry
-	field.SetFilename(QStringLiteral("/custom/elsewhere.cube"));
+	field.set_filename(QStringLiteral("/custom/elsewhere.cube"));
 	EXPECT_EQ(field.library_combo()->currentIndex(), 0);
 
 	// A library path selects its entry
-	field.SetFilename(cube);
+	field.set_filename(cube);
 	EXPECT_GT(field.library_combo()->currentIndex(), 0);
 
 	// Picking a library entry updates the filename and emits the change
 	// signal so the parameter bridge applies it like any other edit
-	field.SetFilename(QString());
-	QSignalSpy spy(&field, &olive::FileField::FilenameChanged);
+	field.set_filename(QString());
+	QSignalSpy spy(&field, &olive::FileField::filename_changed);
 	const int index = field.library_combo()->findData(cube);
 	ASSERT_GE(index, 1);
 	emit field.library_combo()->activated(index);
 
-	EXPECT_EQ(field.GetFilename(), cube);
+	EXPECT_EQ(field.get_filename(), cube);
 	ASSERT_EQ(spy.count(), 1);
 	EXPECT_EQ(spy.first().first().toString(), cube);
 }