core: merge oak-common into oak-core

oak-common is gone; its modules (configstore, xmlutils, ocioutils,
oiioutils, colormath, colortransform, videoparams, ffmpegutils, ...)
now live in oak-core alongside the value types. The render value/GPU
types moved too: backend (wgpu context + DisplayRenderer), color
(ColorProcessor over ocio-rs), texture, frame, and the commonutil
config helpers.

Fix-ups to make the merged tree build and pass tests:

- oak-core Cargo.toml: wgpu back to 25 (the moved backend code is
  written against that API generation); add the toml/quick-xml/image
  deps oak-common carried.
- lib.rs: drop the duplicate 'pub mod error;'.
- error.rs: unified OAKCORE_* codes; restore Error::new() and
  From<OcioError> from oak-common's error type.
- backend.rs/color.rs: oak_core::/oak_render:: self-references
  rewritten to crate::; the shaderfx-dependent GPU effect test moved
  to oak-render's shaderfx tests (shaderfx depends on oak-node and
  cannot live in oak-core).
- oak-render's error module re-exports oak_core::error::{Error,
  Result}; the OAKRENDER_* codes stay as the public-code contract.
- oak-node jobs.rs: ColorProcessor imported from oak_core::color.
- Integration tests repointed at oak_core::{texture, frame, backend,
  color, colormath}.
- the display-ICC regression test treats an empty OAK_DISPLAY_ICC as
  unset, matching displayicc::env_override_icc.

crates/oak-cli/src/engine.rs

@@ -17,7 +17,7 @@
 //! Module-native engine helpers (M14 R2).
 //!
 //! oak-cli links the oak* module rlibs directly (oaknode / oaktimeline /
-//! oakcodec / oakrender / oaktask / oakcommon) instead of the built
+//! oakcodec / oakrender / oaktask / oak_core) instead of the built
 //! liboakengine dylib's C ABI. This module is the CLI's own assembly
 //! layer: it reproduces the facade operations the subcommands need —
 //! project load/create, footage probe, sequence + clip assembly, montage
@@ -43,14 +43,14 @@ use oak_node::project::Project;
 use oak_node::sequence::SequenceBehavior;
 use oak_node::track::{TrackBehavior, TrackListBehavior, TrackType};
 use oak_node::value::VideoParams;
-use oak_timeline::undogeneral::TimelineAddTrackCommand;
-use oak_timeline::undopointer::TrackPlaceBlockCommand;
-use oak_timeline::util::NodeRef;
 use oak_render::manager::RenderManager;
 use oak_render::procpool::bgra8_to_rgba8;
 use oak_render::ticket::{
-	AudioTicketParams, MontageClip, TicketPayload, VideoTicketParams,
+    AudioTicketParams, MontageClip, TicketPayload, VideoTicketParams,
 };
+use oak_timeline::undogeneral::TimelineAddTrackCommand;
+use oak_timeline::undopointer::TrackPlaceBlockCommand;
+use oak_timeline::util::NodeRef;
 
 /// The shared project reference (the modules' domain project handle).
 pub type ProjectRef = Arc<Mutex<Project>>;
@@ -663,7 +663,7 @@ pub fn render_frame(
 	m.tickets.wait(id).map_err(|e| e.to_string())?;
 	let result = m.tickets.result(id).ok_or_else(|| "render ticket produced no result".to_string())?;
 	match &result {
-		Ok(TicketPayload::Video(oak_render::texture::Texture::Cpu(frame))) => {
+		Ok(TicketPayload::Video(oak_core::texture::Texture::Cpu(frame))) => {
 			Ok(RenderedFrame {
 				width: frame.width,
 				height: frame.height,