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/node/project.h

@@ -163,6 +163,12 @@ int oaknode_project_is_new(const OakNodeProject *project);
 int oaknode_project_cache_path(const OakNodeProject *project, char *buf,
 							   int buf_size);
 
+/**
+ * @brief Copy all project settings (Project::copy_settings()).
+ */
+int oaknode_project_copy_settings(OakNodeProject *dst,
+								  const OakNodeProject *src);
+
 /**
  * @brief Cache location setting enum value
  * (Project::get_cache_location_setting(): 0 = default location,