Add a branches_count field to Repository

[ChenTerence]

Feature Description

Currently GET /repos/{owner}/{repo}/branches is the only way to access this information. However, I am already calling GET /users/{username}/repos and would like to avoid the extra request if possible.

Screenshots

No response

[lunny]

But then Gitea needs to sync the data from git data with database which is complicated.

[ChenTerence]

Thank you for your replying!

The reason I gave this recommendation is because I found it is necessary to prepare a report for the information security chief to make a review for the security audit.

And I found it takes a long time to generate a report, so that's why I gave this recommendation.

[lunny]

depends on #22743