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/timelinewidget/tool/tool.h

@@ -19,8 +19,8 @@
 
 ***/
 
-#ifndef TIMELINETOOL_H
-#define TIMELINETOOL_H
+#ifndef OAK_TIMELINETOOL_H
+#define OAK_TIMELINETOOL_H
 
 #include <QDragLeaveEvent>
 
@@ -37,33 +37,33 @@ public:
 	TimelineTool(TimelineWidget *parent);
 	virtual ~TimelineTool();
 
-	virtual void MousePress(TimelineViewMouseEvent *)
+	virtual void mouse_press(TimelineViewMouseEvent *)
 	{
 	}
-	virtual void MouseMove(TimelineViewMouseEvent *)
+	virtual void mouse_move(TimelineViewMouseEvent *)
 	{
 	}
-	virtual void MouseRelease(TimelineViewMouseEvent *)
+	virtual void mouse_release(TimelineViewMouseEvent *)
 	{
 	}
-	virtual void MouseDoubleClick(TimelineViewMouseEvent *)
+	virtual void mouse_double_click(TimelineViewMouseEvent *)
 	{
 	}
 
-	virtual void HoverMove(TimelineViewMouseEvent *)
+	virtual void hover_move(TimelineViewMouseEvent *)
 	{
 	}
 
-	virtual void DragEnter(TimelineViewMouseEvent *)
+	virtual void drag_enter(TimelineViewMouseEvent *)
 	{
 	}
-	virtual void DragMove(TimelineViewMouseEvent *)
+	virtual void drag_move(TimelineViewMouseEvent *)
 	{
 	}
-	virtual void DragLeave(QDragLeaveEvent *)
+	virtual void drag_leave(QDragLeaveEvent *)
 	{
 	}
-	virtual void DragDrop(TimelineViewMouseEvent *)
+	virtual void drag_drop(TimelineViewMouseEvent *)
 	{
 	}
 
@@ -72,11 +72,11 @@ public:
 	Sequence *sequence();
 
 	static Timeline::MovementMode
-	FlipTrimMode(const Timeline::MovementMode &trim_mode);
+	flip_trim_mode(const Timeline::MovementMode &trim_mode);
 
-	static rational SnapMovementToTimebase(const rational &start,
-										   rational movement,
-										   const rational &timebase);
+	static Rational snap_movement_to_timebase(const Rational &start,
+										   Rational movement,
+										   const Rational &timebase);
 
 protected:
 	/**
@@ -85,27 +85,27 @@ protected:
    * Validation is the process of ensuring that whatever movements the user is making are "valid" and "legal". This
    * function's validation ensures that no Ghost's in point ends up in a negative timecode.
    */
-	rational ValidateTimeMovement(rational movement);
+	Rational validate_time_movement(Rational movement);
 
 	/**
    * @brief Validates Ghosts that are moving vertically (track-based)
    *
    * This function's validation ensures that no Ghost's track ends up in a negative (non-existent) track.
    */
-	int ValidateTrackMovement(int movement,
+	int validate_track_movement(int movement,
 							  const QVector<TimelineViewGhostItem *> &ghosts);
 
-	void GetGhostData(rational *earliest_point, rational *latest_point);
+	void get_ghost_data(Rational *earliest_point, Rational *latest_point);
 
-	void InsertGapsAtGhostDestination(MultiUndoCommand *command);
+	void insert_gaps_at_ghost_destination(MultiUndoCommand *command);
 
-	std::vector<rational> snap_points_;
+	std::vector<Rational> snap_points_;
 
 	bool dragging_;
 
 	TimelineCoordinate drag_start_;
 
-	static const int kDefaultDistanceFromOutput;
+	static const int k_default_distance_from_output;
 
 private:
 	TimelineWidget *parent_;
@@ -113,4 +113,4 @@ private:
 
 }
 
-#endif // TIMELINETOOL_H
+#endif // OAK_TIMELINETOOL_H