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/widget/nodeview/nodeviewscene.h

@@ -19,8 +19,8 @@
 
 ***/
 
-#ifndef NODEVIEWSCENE_H
-#define NODEVIEWSCENE_H
+#ifndef OAK_NODEVIEWSCENE_H
+#define OAK_NODEVIEWSCENE_H
 
 #include <QGraphicsScene>
 #include <QTimer>
@@ -39,38 +39,38 @@ class NodeViewScene : public QGraphicsScene {
 public:
 	NodeViewScene(QObject *parent = nullptr);
 
-	void SelectAll();
-	void DeselectAll();
+	void select_all();
+	void deselect_all();
 
-	QVector<NodeViewItem *> GetSelectedItems() const;
+	QVector<NodeViewItem *> get_selected_items() const;
 
 	const QHash<Node *, NodeViewContext *> &context_map() const
 	{
 		return context_map_;
 	}
 
-	Qt::Orientation GetFlowOrientation() const;
+	Qt::Orientation get_flow_orientation() const;
 
-	NodeViewCommon::FlowDirection GetFlowDirection() const
+	NodeViewCommon::FlowDirection get_flow_direction() const
 	{
 		return direction_;
 	}
 
-	void SetFlowDirection(NodeViewCommon::FlowDirection direction);
+	void set_flow_direction(NodeViewCommon::FlowDirection direction);
 
-	bool GetEdgesAreCurved() const
+	bool get_edges_are_curved() const
 	{
 		return curved_edges_;
 	}
 
 public slots:
-	NodeViewContext *AddContext(Node *node);
-	void RemoveContext(Node *node);
+	NodeViewContext *add_context(Node *node);
+	void remove_context(Node *node);
 
 	/**
    * @brief Set whether edges in this scene should be curved or not
    */
-	void SetEdgesAreCurved(bool curved);
+	void set_edges_are_curved(bool curved);
 
 private:
 	QHash<Node *, NodeViewContext *> context_map_;
@@ -84,4 +84,4 @@ private:
 
 }
 
-#endif // NODEVIEWSCENE_H
+#endif // OAK_NODEVIEWSCENE_H