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/pixelsampler/pixelsamplerpanel.cpp

@@ -30,26 +30,26 @@ PixelSamplerPanel::PixelSamplerPanel()
 	: PanelWidget(QStringLiteral("PixelSamplerPanel"))
 {
 	sampler_widget_ = new ManagedPixelSamplerWidget(this);
-	SetWidgetWithPadding(sampler_widget_);
+	set_widget_with_padding(sampler_widget_);
 
 	connect(this, &PixelSamplerPanel::shown, Core::instance(),
-			[] { Core::instance()->RequestPixelSamplingInViewers(true); });
+			[] { Core::instance()->request_pixel_sampling_in_viewers(true); });
 	connect(this, &PixelSamplerPanel::hidden, Core::instance(),
-			[] { Core::instance()->RequestPixelSamplingInViewers(false); });
-	connect(Core::instance(), &Core::ColorPickerColorEmitted, this,
-			&PixelSamplerPanel::SetValues);
+			[] { Core::instance()->request_pixel_sampling_in_viewers(false); });
+	connect(Core::instance(), &Core::color_picker_color_emitted, this,
+			&PixelSamplerPanel::set_values);
 
-	Retranslate();
+	retranslate();
 }
 
-void PixelSamplerPanel::SetValues(const Color &reference, const Color &display)
+void PixelSamplerPanel::set_values(const Color &reference, const Color &display)
 {
-	sampler_widget_->SetValues(reference, display);
+	sampler_widget_->set_values(reference, display);
 }
 
-void PixelSamplerPanel::Retranslate()
+void PixelSamplerPanel::retranslate()
 {
-	SetTitle(tr("Pixel Sampler"));
+	set_title(tr("Pixel Sampler"));
 }
 
 }

app/panel/pixelsampler/pixelsamplerpanel.h

@@ -19,8 +19,8 @@
 
 ***/
 
-#ifndef PIXELSAMPLERPANEL_H
-#define PIXELSAMPLERPANEL_H
+#ifndef OAK_PIXELSAMPLERPANEL_H
+#define OAK_PIXELSAMPLERPANEL_H
 
 #include "panel/panel.h"
 #include "widget/pixelsampler/pixelsampler.h"
@@ -34,14 +34,14 @@ public:
 	PixelSamplerPanel();
 
 public slots:
-	void SetValues(const Color &reference, const Color &display);
+	void set_values(const Color &reference, const Color &display);
 
 private:
-	virtual void Retranslate() override;
+	virtual void retranslate() override;
 
 	ManagedPixelSamplerWidget *sampler_widget_;
 };
 
 }
 
-#endif // PIXELSAMPLERPANEL_H
+#endif // OAK_PIXELSAMPLERPANEL_H