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/input/multicam/multicamnode.h

@@ -16,8 +16,8 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef MULTICAMNODE_H
-#define MULTICAMNODE_H
+#ifndef OAK_MULTICAMNODE_H
+#define OAK_MULTICAMNODE_H
 
 #include "node/node.h"
 #include "node/output/track/tracklist.h"
@@ -34,57 +34,57 @@ public:
 
 	NODE_DEFAULT_FUNCTIONS(MultiCamNode)
 
-	virtual QString Name() const override;
+	virtual QString name() const override;
 	virtual QString id() const override;
-	virtual QVector<CategoryID> Category() const override;
-	virtual QString Description() const override;
+	virtual QVector<CategoryID> category() const override;
+	virtual QString description() const override;
 
 	virtual ActiveElements
-	GetActiveElementsAtTime(const QString &input,
+	get_active_elements_at_time(const QString &input,
 							const TimeRange &r) const override;
 
-	virtual void Value(const NodeValueRow &value, const NodeGlobals &globals,
+	virtual void value(const NodeValueRow &value, const NodeGlobals &globals,
 					   NodeValueTable *table) const override;
 
-	virtual void Retranslate() override;
+	virtual void retranslate() override;
 
-	static const QString kCurrentInput;
-	static const QString kSourcesInput;
-	static const QString kSequenceInput;
-	static const QString kSequenceTypeInput;
+	static const QString k_current_input;
+	static const QString k_sources_input;
+	static const QString k_sequence_input;
+	static const QString k_sequence_type_input;
 
-	int GetCurrentSource() const
+	int get_current_source() const
 	{
-		return GetStandardValue(kCurrentInput).toInt();
+		return get_standard_value(k_current_input).toInt();
 	}
 
-	int GetSourceCount() const;
+	int get_source_count() const;
 
-	static void GetRowsAndColumns(int sources, int *rows, int *cols);
-	void GetRowsAndColumns(int *rows, int *cols) const
+	static void get_rows_and_columns(int sources, int *rows, int *cols);
+	void get_rows_and_columns(int *rows, int *cols) const
 	{
-		return GetRowsAndColumns(GetSourceCount(), rows, cols);
+		return get_rows_and_columns(get_source_count(), rows, cols);
 	}
 
-	void SetSequenceType(Track::Type t)
+	void set_sequence_type(Track::Type t)
 	{
-		SetStandardValue(kSequenceTypeInput, t);
+		set_standard_value(k_sequence_type_input, t);
 	}
 
-	static void IndexToRowCols(int index, int total_rows, int total_cols,
+	static void index_to_row_cols(int index, int total_rows, int total_cols,
 							   int *row, int *col);
 
-	static int RowsColsToIndex(int row, int col, int total_rows, int total_cols)
+	static int rows_cols_to_index(int row, int col, int total_rows, int total_cols)
 	{
 		return col + row * total_cols;
 	}
 
-	virtual Node *GetConnectedRenderOutput(const QString &input,
+	virtual Node *get_connected_render_output(const QString &input,
 										   int element = -1) const override;
-	virtual bool IsInputConnectedForRender(const QString &input,
+	virtual bool is_input_connected_for_render(const QString &input,
 										   int element = -1) const override;
 
-	virtual QVector<QString> IgnoreInputsForRendering() const override;
+	virtual QVector<QString> ignore_inputs_for_rendering() const override;
 
 protected:
 	virtual void InputConnectedEvent(const QString &input, int element,
@@ -93,11 +93,11 @@ protected:
 										Node *output) override;
 
 private:
-	TrackList *GetTrackList() const;
+	TrackList *get_track_list() const;
 
 	Sequence *sequence_;
 };
 
 }
 
-#endif // MULTICAMNODE_H
+#endif // OAK_MULTICAMNODE_H