R8: finish app/ pure C ABI migration (P3-P9) and make OTIO required

- app/ no longer includes engine C++ headers nor holds engine C++ types:
  engine access goes through the oakengine C ABI plus C++ wrappers
  (oakutil/oaknode.h, oakutil/oakvideo.h) and app-local mirror types
  (tooltypes, trackreferencehandle, timelinecommonapp, keyframetypes,
  subtitleapp, serializedlayoutinfoapp, nodevaluehandle, sliderdisplaytypeapp)
- engine: new C ABI functions for block/track/clip/transition navigation
  and predicates, links, caches, waveform/playback, disk folder,
  sequence_track_list, node_free, footage_is_valid, block_get_track,
  get_brush; loadotio/saveotio ported to the current engine API
- OTIO is now a required dependency: CI and CD build it on every
  platform, FindOpenTimelineIO fixed for OTIO 0.16/0.19 (the old deps
  include requirement silently disabled OTIO everywhere), runtime
  libraries are bundled into packages and copied next to macOS binaries
  (oak_copy_otio_runtime)
- fix ProjectViewModel drag&drop mime read/write size mismatch (segfault)
- unify color label naming (k_olive -> "Oak") in the app-side mirror
- docs: OTIO required, FFmpeg minimum corrected to 6.0 (en/zh)
- gtest suite: 1925 passed, 0 failed

app/widget/nodeparamview/nodeparamviewarraywidget.cpp

@@ -24,12 +24,10 @@
 #include <QEvent>
 #include <QHBoxLayout>
 
-#include "node/node.h"
-
 namespace olive
 {
 
-NodeParamViewArrayWidget::NodeParamViewArrayWidget(Node *node,
+NodeParamViewArrayWidget::NodeParamViewArrayWidget(oak::Node node,
 												   const QString &input,
 												   QWidget *parent)
 	: QWidget(parent)
@@ -42,7 +40,7 @@ NodeParamViewArrayWidget::NodeParamViewArrayWidget(Node *node,
 	count_lbl_ = new QLabel();
 	layout->addWidget(count_lbl_);
 
-	bridge_->subscribe(reinterpret_cast<void *>(node_),
+	bridge_->subscribe(reinterpret_cast<void *>(node_.handle()),
 					   OAKENGINE_EVENT_NODE_INPUT_ARRAY_SIZE_CHANGED);
 	connect(bridge_, &EngineEventBridge::node_input_array_size_changed, this,
 			[this](OakEngineNode *, const QString &input, int old_size,
@@ -50,7 +48,7 @@ NodeParamViewArrayWidget::NodeParamViewArrayWidget(Node *node,
 				update_counter(input, old_size, new_size);
 			});
 
-	update_counter(input_, 0, node_->input_array_size(input_));
+	update_counter(input_, 0, oak::Input(node_.handle(), input_).array_size());
 }
 
 void NodeParamViewArrayWidget::mouseDoubleClickEvent(QMouseEvent *event)