build: split the engine into liboakengine.so; worker drops the UI entirely

Physical split: app/{audio,cli,codec,common,config,node,pluginSupport,
render,task,timeline,undo,tool,shaders} plus coreengine, version and
ui/icons+colorcoding move to a new top-level engine/ tree, built as
liboakengine.so (shared). The render backends (oakgl/oakvulkan) move
with it and link the engine library instead of embedding a static
render-core subset (libolive-rendercore is gone).

- oak-render-worker now links liboakengine instead of the whole
  libolive-editor object set: 336MB -> 2.9MB, no Qt Widgets UI
- the editor links liboakengine for the engine and keeps only UI
  objects in libolive-editor
- install/packaging: GNUInstallDirs libdir on Linux, bundle copy on
  macOS, oakengine.dll staged for NSIS, AppImage validation entry
- fix backend lookup for the new layout: DynamicRenderer searched
  ../app but backends now live in engine/; a stale pre-split liboakgl
  in the build tree got dlopened instead, re-initialized and later
  destroyed the interposed engine statics (full-suite segfault at
  DialogSequenceParameterTab, found via gdb watchpoint)

engine/render/renderjobtracker.cpp

@@ -0,0 +1,75 @@
+/***
+
+  Olive - Non-Linear Video Editor
+  Copyright (C) 2022 Olive Team
+  Modifications Copyright (C) 2025 mikesolar
+
+  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/>.
+
+***/
+
+#include "renderjobtracker.h"
+
+namespace olive
+{
+
+void RenderJobTracker::insert(const TimeRange &range, JobTime job_time)
+{
+	// First remove any ranges that overlap this one (code copied from TimeRangeList::remove)
+	TimeRangeList::util_remove(&jobs_, range);
+
+	// Now append the job
+	TimeRangeWithJob job(range, job_time);
+	jobs_.push_back(job);
+}
+
+void RenderJobTracker::insert(const TimeRangeList &ranges, JobTime job_time)
+{
+	foreach (const TimeRange &r, ranges) {
+		insert(r, job_time);
+	}
+}
+
+void RenderJobTracker::clear()
+{
+	jobs_.clear();
+}
+
+bool RenderJobTracker::isCurrent(const Rational &time, JobTime job_time) const
+{
+	for (auto it = jobs_.crbegin(); it != jobs_.crend(); it++) {
+		if (it->contains(time)) {
+			return job_time >= it->get_job_time();
+		}
+	}
+
+	return false;
+}
+
+TimeRangeList
+RenderJobTracker::getCurrentSubRanges(const TimeRange &range,
+									  const JobTime &job_time) const
+{
+	TimeRangeList current_ranges;
+
+	for (auto it = jobs_.crbegin(); it != jobs_.crend(); it++) {
+		if (job_time >= it->get_job_time() && it->overlaps_with(range)) {
+			current_ranges.insert(it->intersected(range));
+		}
+	}
+
+	return current_ranges;
+}
+
+}