chore(core) Default to friendly personality (#10305)

## Summary
Update default personality to friendly

## Testing
- [x] Unit tests pass

codex-rs/app-server/tests/suite/v2/thread_resume.rs

@@ -402,7 +402,7 @@ async fn thread_resume_accepts_personality_override() -> Result<()> {
         .send_thread_resume_request(ThreadResumeParams {
             thread_id: thread.id.clone(),
             model: Some("gpt-5.2-codex".to_string()),
-            personality: Some(Personality::Friendly),
+            personality: Some(Personality::Pragmatic),
             ..Default::default()
         })
         .await?;