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/node/gizmo/point.h

@@ -19,8 +19,8 @@
 
 ***/
 
-#ifndef POINTGIZMO_H
-#define POINTGIZMO_H
+#ifndef OAK_POINTGIZMO_H
+#define OAK_POINTGIZMO_H
 
 #include <QPointF>
 
@@ -32,48 +32,48 @@ namespace olive
 class PointGizmo : public DraggableGizmo {
 	Q_OBJECT
 public:
-	enum Shape { kSquare, kCircle, kAnchorPoint };
+	enum Shape { k_square, k_circle, k_anchor_point };
 
 	explicit PointGizmo(const Shape &shape, bool smaller,
 						QObject *parent = nullptr);
 	explicit PointGizmo(const Shape &shape, QObject *parent = nullptr);
 	explicit PointGizmo(QObject *parent = nullptr);
 
-	const Shape &GetShape() const
+	const Shape &get_shape() const
 	{
 		return shape_;
 	}
-	void SetShape(const Shape &s)
+	void set_shape(const Shape &s)
 	{
 		shape_ = s;
 	}
 
-	const QPointF &GetPoint() const
+	const QPointF &get_point() const
 	{
 		return point_;
 	}
-	void SetPoint(const QPointF &pt)
+	void set_point(const QPointF &pt)
 	{
 		point_ = pt;
 	}
 
-	bool GetSmaller() const
+	bool get_smaller() const
 	{
 		return smaller_;
 	}
-	void SetSmaller(bool e)
+	void set_smaller(bool e)
 	{
 		smaller_ = e;
 	}
 
-	virtual void Draw(QPainter *p) const override;
+	virtual void draw(QPainter *p) const override;
 
-	QRectF GetClickingRect(const QTransform &t) const;
+	QRectF get_clicking_rect(const QTransform &t) const;
 
 private:
-	static double GetStandardRadius();
+	static double get_standard_radius();
 
-	QRectF GetDrawingRect(const QTransform &transform, double radius) const;
+	QRectF get_drawing_rect(const QTransform &transform, double radius) const;
 
 	Shape shape_;
 
@@ -84,4 +84,4 @@ private:
 
 }
 
-#endif // POINTGIZMO_H
+#endif // OAK_POINTGIZMO_H