Treat inference hook denials as terminal errors (#60511)

## Why

An explicit denial from a workspace inference hook should stop the request, including retries and compaction model fallback.

## What changed

Recognize `inference_hook_denied` provider errors and preserve the provider's message, with a fallback when none is supplied. Expose the distinct `inferenceHookDenied` error through the app-server protocol and generated schemas and SDK types. Treat the denial as non-retryable during turns, compaction, and guardian review.

## Testing

Add coverage for terminal denials over HTTP, SSE, and WebSocket, error serialization and persistence in `thread/read`, and compaction failures that preserve token usage and history without retrying or falling back to another model.

GitOrigin-RevId: 2ebd480f01e52f4e6bd3db8a0f92d5814d18ccb1

codex-rs/app-server-protocol/src/protocol/v2/shared.rs

@@ -83,6 +83,8 @@ pub enum CodexErrorInfo {
     ModelNotFound,
     // Capacity is unavailable on a route restricted by server policy.
     PolicyCapacityUnavailable,
+    /// The workspace's inference hook explicitly denied this request.
+    InferenceHookDenied,
     CyberPolicy,
     MisalignmentPolicyViolation,
     TooManyDenials,
@@ -163,6 +165,7 @@ impl From<CoreCodexErrorInfo> for CodexErrorInfo {
                 CodexErrorInfo::PolicyCapacityUnavailable
             }
             CoreCodexErrorInfo::CyberPolicy => CodexErrorInfo::CyberPolicy,
+            CoreCodexErrorInfo::InferenceHookDenied => CodexErrorInfo::InferenceHookDenied,
             CoreCodexErrorInfo::BioPolicy => CodexErrorInfo::Other,
             CoreCodexErrorInfo::MisalignmentPolicyViolation => {
                 CodexErrorInfo::MisalignmentPolicyViolation

codex-rs/app-server-protocol/src/protocol/v2/tests.rs

@@ -4907,6 +4907,10 @@ fn core_error_info_converts_to_camel_case() {
             json!("policyCapacityUnavailable"),
         ),
         (CoreCodexErrorInfo::CyberPolicy, json!("cyberPolicy")),
+        (
+            CoreCodexErrorInfo::InferenceHookDenied,
+            json!("inferenceHookDenied"),
+        ),
         (CoreCodexErrorInfo::BioPolicy, json!("other")),
         (CoreCodexErrorInfo::InvalidPrompt, json!("other")),
         (
@@ -4918,9 +4922,11 @@ fn core_error_info_converts_to_camel_case() {
             json!("rateLimitExceeded"),
         ),
     ] {
+        let converted = CodexErrorInfo::from(core);
+        assert_eq!(serde_json::to_value(&converted).unwrap(), expected);
         assert_eq!(
-            serde_json::to_value(CodexErrorInfo::from(core)).unwrap(),
-            expected
+            serde_json::from_value::<CodexErrorInfo>(expected).unwrap(),
+            converted
         );
     }
 }