feat(otel): propagate session.id to spans and log records (#7490)

Signed-off-by: Adrian Cole <adrian@tetrate.io>

crates/goose/src/providers/base.rs

@@ -459,6 +459,10 @@ pub trait Provider: Send + Sync {
     fn get_name(&self) -> &str;
 
     /// Primary streaming method that all providers must implement.
+    ///
+    /// Note: Do not add `#[instrument]` here — the call sites (`complete` and
+    /// `stream_response_from_provider`) create the telemetry span so that
+    /// `session.id` is set once rather than in every provider.
     async fn stream(
         &self,
         model_config: &ModelConfig,
@@ -469,6 +473,10 @@ pub trait Provider: Send + Sync {
     ) -> Result<MessageStream, ProviderError>;
 
     /// Complete with a specific model config.
+    #[tracing::instrument(
+        skip(self, model_config, session_id, system, messages, tools),
+        fields(session.id = %session_id, gen_ai.request.model = %model_config.model_name)
+    )]
     async fn complete(
         &self,
         model_config: &ModelConfig,