feat(goose): standardize agent-session-id for session correlation (#6626)

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

crates/goose/src/agents/mcp_client.rs

@@ -859,8 +859,8 @@ mod tests {
         let mut extensions = Extensions::new();
         extensions.insert(
             from_value::<Meta>(json!({
-                "GOOSE-SESSION-ID": "old-session-1",
-                "Goose-Session-Id": "old-session-2",
+                SESSION_ID_HEADER: "old-session-1",
+                "Agent-Session-Id": "old-session-2",
                 "other-key": "preserve-me"
             }))
             .unwrap(),

crates/goose/src/session_context.rs

@@ -1,6 +1,6 @@
 use tokio::task_local;
 
-pub const SESSION_ID_HEADER: &str = "goose-session-id";
+pub const SESSION_ID_HEADER: &str = "agent-session-id";
 
 task_local! {
     pub static SESSION_ID: Option<String>;