refactor(task,render): RenderTask family over a new oakrender ticket C ABI

- oakrender: new ticket family (render_frame/render_audio with finished
  callback, result frame/samples access, cancel/wait), project copier
  C API, cache get_invalidated_ranges, manager set_aggressive_gc
- oaknode: node_copy_inputs, set_value_hint_track, viewer params
  setters, video frame cache borrowed outlet, project copy_settings
- oakcodec: encoder desired pixel format, export format extension,
  encoding generate_matrix, custom range in encoding params POD
- oaktask: RenderTask orchestrates oakrender tickets (no Qt threads/
  watchers), PreCacheTask and ExportTask rewritten over the oaknode/
  oakrender/oakcodec C ABIs; frames cross from oakrender to oakcodec
  handles by pixel copy (different control blocks)
- the two-step texture/download render path collapses into single-step
  (tickets always yield frames); subtitle sidecar kept
- tests: 105 in build-oaktask (export/precache factory paths,
  construction, conform end-to-end); regressions all green

include/task/project.h

@@ -21,9 +21,12 @@
 #ifndef OAK_EDITOR_TASK_PROJECT_H
 #define OAK_EDITOR_TASK_PROJECT_H
 
+#include "codec/encoder.h"
+#include "node/colormanager.h"
 #include "node/footage.h"
 #include "node/node.h"
 #include "node/project.h"
+#include "node/sequence.h"
 #include "task/task.h"
 #include "undo/undocommand.h"
 
@@ -67,6 +70,15 @@ int oaktask_import_invalid_count(OakTaskTask *t);
 int oaktask_import_invalid_at(OakTaskTask *t, int index, char *buf,
 							  int buf_size);
 
+/** @brief olive::PreCacheTask. */
+OakTaskTask *oaktask_create_precache(OakNodeFootage *footage, int index,
+									 OakNodeSequence *sequence);
+
+/** @brief olive::ExportTask (params POD from codec/encoder.h). */
+OakTaskTask *oaktask_create_export(OakNodeNode *viewer,
+								   OakNodeColorManager *color_manager,
+								   const oakcodec_encoding_params *params);
+
 /**
  * @brief Image-sequence confirmation callback (facade/UI concern;
  *        olive::ProjectImportTask::set_image_sequence_confirm_callback).