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/pluginSupport/olivehost.h

@@ -0,0 +1,105 @@
+/*
+ * Oak Video Editor - Non-Linear Video Editor
+ * Copyright (C) 2025 Olive CE Team
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef OAK_OLIVE_HOST_H
+#define OAK_OLIVE_HOST_H
+#include "node/plugins/plugin.h"
+#include "ofxhHost.h"
+#include "ofxhImageEffectAPI.h"
+#include "ofxCore.h"
+#include "ofxhImageEffect.h"
+
+#include <QVariant>
+#include <cstdint>
+#include <QString>
+#include <QMap>
+#include <any>
+#include <list>
+#include <memory>
+#include <qlist.h>
+namespace olive
+{
+namespace plugin
+{
+enum class HostMessageType { error, warning, message };
+struct HostPersistentMessage {
+	HostMessageType type;
+	QString message;
+};
+
+void load_plugins(QString path);
+class OliveHost : public OFX::Host::ImageEffect::Host {
+public:
+	OliveHost();
+	~OliveHost() override;
+	void destroy_instance(OFX::Host::ImageEffect::Instance *instance);
+
+	bool pluginSupported(OFX::Host::ImageEffect::ImageEffectPlugin *plugin,
+						 std::string &reason) const override
+	{
+		if (!plugin) {
+			reason = "null plugin";
+			return false;
+		}
+		if (plugin->getContexts().empty()) {
+			reason = "no supported contexts (describe failed)";
+			return false;
+		}
+		return true;
+	};
+
+	OFX::Host::ImageEffect::Instance *
+	newInstance(void *client_data,
+				OFX::Host::ImageEffect::ImageEffectPlugin *plugin,
+				OFX::Host::ImageEffect::Descriptor &desc,
+				const std::string &context) override;
+
+	std::shared_ptr<OFX::Host::ImageEffect::Descriptor>
+	makeDescriptor(OFX::Host::ImageEffect::ImageEffectPlugin *plugin) override;
+
+	std::shared_ptr<OFX::Host::ImageEffect::Descriptor>
+	makeDescriptor(const OFX::Host::ImageEffect::Descriptor &root_context,
+				   OFX::Host::ImageEffect::ImageEffectPlugin *plugin) override;
+
+	std::shared_ptr<OFX::Host::ImageEffect::Descriptor>
+	makeDescriptor(const std::string &bundle_path,
+				   OFX::Host::ImageEffect::ImageEffectPlugin *plugin) override;
+	/// vmessage
+	virtual OfxStatus vmessage(const char *type, const char *id,
+							   const char *format, va_list args);
+
+	/// vmessage
+	virtual OfxStatus setPersistentMessage(const char *type, const char *id,
+										   const char *format, va_list args);
+	/// vmessage
+	virtual OfxStatus clearPersistentMessage();
+
+#ifdef OFX_SUPPORTS_OPENGLRENDER
+	/// @see OfxImageEffectOpenGLRenderSuiteV1.flushResources()
+	virtual OfxStatus flushOpenGLResources() const
+	{
+		return kOfxStatFailed;
+	};
+#endif
+private:
+	QList<std::shared_ptr<OFX::Host::ImageEffect::Descriptor>> descriptors_;
+	QList<std::shared_ptr<OFX::Host::ImageEffect::Instance>> instances_;
+	QList<HostPersistentMessage> persistent_messages_;
+};
+}
+}
+#endif