fix: pentest session ID propagation, target name resolution, BSON field paths

- Set session.id from insert_one result so orchestrator has the ID
- Enrich sessions with target_name by joining DAST targets in server fns
- Fix _id.$oid BSON field path for target dropdown and session list
- Fix send_message URL to /chat (was /messages)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

compliance-agent/src/api/handlers/pentest.rs

@@ -76,7 +76,7 @@ pub async fn create_session(
     let mut session = PentestSession::new(req.target_id.clone(), strategy);
     session.repo_id = target.repo_id.clone();
 
-    agent
+    let insert_result = agent
         .db
         .pentest_sessions()
         .insert_one(&session)
@@ -88,6 +88,9 @@ pub async fn create_session(
             )
         })?;
 
+    // Set the generated ID back on the session so the orchestrator has it
+    session.id = insert_result.inserted_id.as_object_id();
+
     let initial_message = req.message.unwrap_or_else(|| {
         format!(
             "Begin a {} penetration test against {} ({}). \