feat: complete Rust backend UI compatibility

src/transformers/canonical/response.rs

@@ -1,6 +1,6 @@
 // Canonical response — unified output format for all providers
 use crate::transformers::canonical::request::CanonicalMessage;
-use crate::transformers::canonical::types::{StreamDelta, ToolCall, Usage};
+use crate::transformers::canonical::types::{StreamDelta, Usage};
 use serde::{Deserialize, Serialize};
 
 /// Unified internal response format

src/transformers/openai/chat/inbound.rs

@@ -1,4 +1,6 @@
 // OpenAI chat/completions request → CanonicalRequest parser
+#![allow(clippy::bind_instead_of_map, clippy::manual_map)]
+
 use crate::transformers::canonical::{
     CanonicalMessage, CanonicalRequest, ContentPart, ReasoningConfig, Role, ToolCall, ToolChoice,
     ToolDefinition,

src/transformers/openai/chat/outbound.rs

@@ -1,6 +1,6 @@
 // CanonicalResponse → OpenAI /v1/chat/completions JSON formatter
 use crate::transformers::canonical::{
-    CanonicalChoice, CanonicalMessage, CanonicalResponse, ContentPart, Role, Usage,
+    CanonicalChoice, CanonicalMessage, CanonicalResponse, ContentPart, Role,
 };
 use serde_json::{json, Value};
 
@@ -115,7 +115,7 @@ fn format_content_parts(parts: &[ContentPart]) -> Value {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::transformers::canonical::{CanonicalMessage, CanonicalResponse};
+    use crate::transformers::canonical::CanonicalResponse;
 
     #[test]
     fn test_format_simple_response() {

src/transformers/openai/chat/stream.rs

@@ -1,4 +1,6 @@
 // OpenAI SSE stream parser and formatter
+#![allow(clippy::unnecessary_filter_map)]
+
 use crate::transformers::canonical::{
     CanonicalStreamChoice, CanonicalStreamEvent, Role, StreamDelta, Usage,
 };