Bug: A session shows title and worktree name but no run/open/open canvas icon are shown

Bug:
Usually a session shows the title, worktree name, and on the right the run button and open button along with the open canvas icon.
I see a problematic session shows title and worktree name but no buttons for run, open, nor canvas icon.

---
| Field | Value |
| --- | --- |
| App version | 1.0.21 |
| OS | Windows 10.0.26200 |
| Theme | GitHub |
| Path | /chat |
| Tenure | Week 6 |

Reproduce the missing controls on the /chat path using app version 1.0.21 on Windows 10, comparing the problematic session with a normal session. Trace the session UI entry point to determine why the run, open, and canvas controls are absent. Done means the affected session displays all three controls consistently.

索引モデルが issue の本文から書いたものです。