Include session name in status line data

Question

## Summary
The status line JSON includes `session_id` but not the session name set via `/name` or `/rename`.

## Request
Include `session.name` (or similar field) in the status line JSON payload.

## Use Case
Display the human-readable session name instead of the UUID:
```
my-feature-work | $2.50 | 15K/200K tokens (7.5%)
```

Currently only the session ID is available, resulting in less readable output like:
```
e29f3d56-6691-46cc-96a8-02e44edf246c | $2.50 | ...
```