Expose actionable ids for opaque provider failures

Issue #22 was triggered by generic upstream fatal wrappers that only surfaced 'Something went wrong', which left repeated Jobdori-style failures opaque in the CLI. Capture provider request ids on error responses, classify the known generic wrapper as provider_internal, and prefix the user-visible runtime error with the failure class plus session/trace identifiers so operators can correlate the failure quickly.

Constraint: Keep the fix small and user-safe without redesigning the broader runtime error taxonomy
Constraint: Preserve existing non-generic error text unless the wrapper is the known opaque fatal surface
Rejected: Broadly rewriting every runtime error into classified envelopes | unnecessary scope expansion for issue #22
Confidence: high
Scope-risk: narrow
Reversibility: clean
Directive: If more opaque wrappers appear, extend the marker list and classification helper rather than reintroducing raw wrapper text alone
Tested: cargo test -p api detects_generic_fatal_wrapper_and_classifies_it_as_provider_internal -- --nocapture; cargo test -p api retries_exhausted_preserves_nested_request_id_and_failure_class -- --nocapture; cargo test -p rusty-claude-cli opaque_provider_wrapper_surfaces_failure_class_session_and_trace -- --nocapture; cargo test -p rusty-claude-cli retry_exhaustion_preserves_internal_failure_class_for_generic_provider_wrapper -- --nocapture; cargo test --workspace
Not-tested: Live upstream reproduction of the Jobdori failure against a real provider session

rust/crates/api/src/providers/openai_compat.rs

@@ -906,6 +906,7 @@ async fn expect_success(response: reqwest::Response) -> Result<reqwest::Response
         return Ok(response);
     }
 
+    let request_id = request_id_from_headers(response.headers());
     let body = response.text().await.unwrap_or_default();
     let parsed_error = serde_json::from_str::<ErrorEnvelope>(&body).ok();
     let retryable = is_retryable_status(status);
@@ -918,6 +919,7 @@ async fn expect_success(response: reqwest::Response) -> Result<reqwest::Response
         message: parsed_error
             .as_ref()
             .and_then(|error| error.error.message.clone()),
+        request_id,
         body,
         retryable,
     })