- The compare page head title should be `compare` but not `new pull
request`.
- Use `UnstableGuessRefByShortName` instead of duplicated functions
calls.
- Direct-compare, tags, commits compare will not display `New Pull
Request` button any more.
The new screenshot
<img width="1459" height="391" alt="image"
src="https://github.com/user-attachments/assets/64e9b070-9c0b-41d1-b4b8-233b96270e1b"
/>
---------
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>