clippy: clear the workspace errors and apply the machine fixes

- Mark the raw-pointer interop entry points unsafe with # Safety docs
  (oak-core upload/download/frame-from-pixels, oak-audio convert) and
  satisfy the existing callers (tests).
- mut_from_ref: allow with the ABI contract documented (the handle
  get_mut helpers in oak-timeline/oak-render/oak-task take the shared
  reference the C ABI passes; exclusivity is the caller's unsafe
  contract).
- Fix the eq_op in the white-balance normalization (green / green).
- Apply cargo clippy --fix across the workspace (redundant closures and
  field names, field reassignment, items after test modules, ...).
- Revert the replace_box fix in image_effect's clip_define: a
  redefinition must allocate a new box, otherwise the old clip handle
  stays valid and the HS-map replace contract (clip != clip2) breaks.
- 283 warnings remain; they are all non-machine-applicable
  (chunks_exact -> as_chunks needs a manual iter_mut, too_many_arguments,
  complex types, missing Safety docs, ...) and are tracked as the
  follow-up.

crates/oak-node/src/nodes/cropdistortnode.rs

@@ -410,6 +410,17 @@ fn create_crop_side_input(core: &mut NodeCore, id: &str) {
 	core.add_input(input);
 }
 
+/// Register this node type (C++ factory entry for
+/// `org.olivevideoeditor.Olive.crop`).
+pub fn register(meta: &mut Vec<NodeMeta>) {
+	meta.push(NodeMeta {
+		type_id: "org.olivevideoeditor.Olive.crop",
+		name: "Crop",
+		categories: &[Category::Distort],
+		create,
+	});
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -528,14 +539,3 @@ mod tests {
 		assert_eq!(dup.name(), "Crop");
 	}
 }
-
-/// Register this node type (C++ factory entry for
-/// `org.olivevideoeditor.Olive.crop`).
-pub fn register(meta: &mut Vec<NodeMeta>) {
-	meta.push(NodeMeta {
-		type_id: "org.olivevideoeditor.Olive.crop",
-		name: "Crop",
-		categories: &[Category::Distort],
-		create,
-	});
-}